Gay & 17: Falling for my best friend. LONG

Hey, over the past few weeks I've grown awfully close to this guy I've had a crush on for about 3 years now. I guess we were always nice acquaintances, sort of friendly to each other but didn't really develop a friendship until about a month or so ago.We've always had classes together but we never really became close like we are now. It started when he had another breakup with his on and off again girlfriend of 3 years. He confided in me one day while I was near the library during my off period. I'm an extremely empathetic person and I felt for him. I did my best to cheer him, giving him advice which he took and the three of us (his ex, him and I) all were friends. Around New Years the two started dating again but shortly broke up again earlier this month.Basically she got tired of him and as of now all she does is use him. She bitches at him in public about how clingy he is he, "just tries to be her friend.", as he says. I admit, he is obsessive towards her and I can see why she gets so upset. All the while, he continues to follow her around like a sad puppy.Anyways, that would happen non stop for weeks now: He'd try to talk to her, she's get mad, and I comforted him.At first we would text constantly, me being a good friend just checking on him but after a week of that gross cycle of a relationship I mentioned above, it wasn't until he told me he loved me that I admitted to myself that I can't deny my feelings for him. I told him that I loved him back but we also kept it like a, "a love you like a friend type of deal." That made me want to shoot myself, haha. (Just imagine getting a message in the dead of night from the person you've liked forever that they love you, just for them to say as a friend a minute later.)Things were nice between us but I've told my friends all of this that's been going on, trying to seek some advice to deal with me liking him and my crush being caught on his ex. One of my best friends told me to just stop having feeling for him but I just couldn't stop. I was getting sad, he wouldn't text back for hours at a time and I'd start to feel bad about myself and my circumstances because I wasn't a girl, that I can never be his. Then I would tell myself that I shouldn't be obsessing over this guy, he'll never see me that way and I shouldn't be upset. I'm gay he's _____. (Well idk, one of my gay guy friends almost talked him into having sex with him, that's something else entirely.) (knowing that and being the optimistic hopeless romantic I was, thought that I, his best friend, could have a good shot a being with him.)He's always making plans with me and then canceling because his other friends or he's busy. Which I understand but it hurts because of my feeling for him. Now I check social media and he's out with this girl, making me think that I could have missed my shot with him. Should I have told him how I feel? I don't know anymore, this is so long already and I don't know what I'm going to do. I'm going to try to be happy for him. Some friends are telling me I'm being used because he only comes to me when he's down and that if he really wanted to hang out with me or anything, he would make time. Idk, sorry this is so long. I'm grateful for whatever advice I get.