Dating a Japanese Guy...Need advice

Sorry this post is kinda long, I could use some advice..I'm an american with a Japanese boyfriend. He's only lived here a few years. We've been together for five months now and we've hit a bit of a bump. I've had a few people suggest to me that the issue might be cultural, so I'm looking for some insight...Everything was going great for a long time. We were very close. Our schedules are very different from each others, (I'm 9-5PM, he works from 4PM-11PM most nights) but still we'd chill at each other's apartments some nights and we both have Sundays off.He went home to Japan for 2 weeks. I took the morning off from work to go with him to the airport. He had decided to come out of the closet to his parents which he was very nervous about. We talked regularly during the two weeks and I tried my best to give him words of strength. He came out on his last day there and it went better than expected, though his mother was still upset she accepted him. His dad was fine with it right away.I had hoped to surprise him at the airport when he got back but I couldn't get there in time. We had just had a snowstorm over the weekend and the subways were running badly. I figured he wasn't expecting me so I didn't think anything of it. Plus I figured he'd be exhausted from traveling.The day after was his birthday. He had said he wanted italian food and to visit the new world trade center observation deck. I was looking for italian restaurants online but i also knew he was a fan of thai and i knew a great atmospheric thai place. So i texted him saying "hey i know you said you wanted Italian but I know this great thai place if you're into that instead?" I figured he'd either say yes or that he wanted to stick to Italian. I also suggested having dinner that night and visiting world trade on Sunday. Most Americans I know don't have a problem with continuing birthday celebrations on the weekend after their birthday. He said he was cool with both.Birthday came, he seemed a little off at first but came around after some wine. We had a great night, went to a bar after. Sunday came and again we had a great time. At this point btw he changed his Facebook status to in a relationship (i had already done this but didn't tag him because he wasn't out of the closet yet). But then the next weekend approached, he told me he'd rather hang with a female friend on Friday and me come over Saturday-Sunday. No problem. But then he said he didn't want me coming over Saturday either. I asked if something was wrong and he said he wanted to talk about something s to make our relationship stronger. I was baffled because everything seemed wonderful.Turns out he was disappointed that I didn't meet him at the airport but it was ok because he knew i thought about it. And he didn't understand why I brought him for Italian food and he really wanted to go to World Trade that night, even though we went on Sunday instead. We talked it out. But the next time I saw him he was very quiet, very sad. I insisted he tell me what was wrong and he said he was still really disappointed about his birthday. We talked it out again. I felt terrible about it. At this point btw we'd been saying I love you (he initiated) and all throughout his trip to Japan he was "I miss you i miss you". So what seemed so minor to me was having an intense effect on him I didn't understand.The worst part was that he wanted to only see me Saturday-Sunday for awhile. And he wanted to postpone meeting my dad which I was really looking forward to, as was my father as he'd never actually met anyone I dated. I was waiting for something serious. This all had me very confused and rather gutted.I talked with my Singaporean friend about it, he's very insightful when it comes to Asian culture. He told me that Japanese guys sometimes don't say how they feel and that they love grand gestures. I said it's like he lives in a romantic movie and my friend said... exactly, very Japanese.So Valentines day I made a plan. He was being a little quiet at dinner but not as sad seeming.I presented him with his gifts... A gift certificate to his favorite store, a stuffed animal dog (his favorite breed.... i know super schmaltzy but he likes that kind of stuff) and a surprise that I was taking him to a Valentines day haunted house (he likes haunted houses and we had to cancel our halloween plans because i was sick). I nailed it. He was thrilled. He grabbed my hand and was so happy. We had a great night together. He was so happy that he felt like he could talk to me. That night he said "I don't want to lose you ever." And we were back on to visit my dad (i hadn't told my dad yet that he wanted to postpone). He came over the next day and we had another great night. He was super cuddly.Then...everything changed again. He was being super quiet the next Sunday. And not as physically close as normal. That night I had to ask him to sit with me while we watched TV. He lay down and put his head on my lap. Few days later I asked about trying to spend a few hours on the weekdays together because he's going back to school soon and is going to be even busier than normal. He didn't answer.Now here's where I really need advice...he says that sometimes he's really happy but sometimes he gets really sad and feels like he doesn't love me. (OUCH). There does not seem to be any particular reason for this. He also wanted to postpone our visit to my dad again because he knows it's really important to me and we should go when our relationship is stronger. He also wants to only get together Saturday-sunday. It was back to where we were. And he assured me there's nothing I've done wrong. I'M SO CONFUSED. I've really fallen for him. I can't help but think when he says "sometimes i don't feel like I love you anymore" there's something else he's trying to say. Like i don't think he means it as cruelly as it sounds. He insists that he doesn't want to breakup. He also insists that he doesn't know himself why he feels the way he does. I suggested that he's overwhelmed. He's thinking of switching jobs, he just came out to his family (and some friends), he's going back to school and this is one of his first relationships. He had told me awhile back that his last boyfriend was really mean to him so he gets scared (hence his overreaction to the birthday thing), i told him i'm not that guy. I don't cheat, and don't ignore him. It's the back and forth that's killing me. And the thing about him not wanting to spend too much time together confuses the hell out of me. If he still wants to be in a relationship then what difference does it make? I barely see him as it is. But he's insisting on a Saturday-sunday schedule. I considered maybe he was cheating but I REAAAALLLLY don't think he's the type. I don't know what to do. He says he wants to change his feelings and doesn't know whats wrong with him. I don't know if this stems from a cultural difference or if it's just him. I could really use some advice here guys. Sorry for the length of the post!