Am I becoming gay?

A short description of me: I'm 18 years old and I've always been and (still am) into females. I've been with many girls, but my last ex girlfriend decided to suck my so-called (at the time) best friend's wiener. I've had trust and love issues ever since.Anyway, there's this guy...Over the course of 1 year he became an incredible best friend. He's the most beautiful person, inside and out. We went through so much bullshit together and I always felt like I can trust him with anything. He means the world to me and seeing him even slightly unhappy breaks my heart. For the last two weeks we've been seeing each other almost every day and the second he leaves, I start getting worried and sad. Cause I feel like something could happen to him and I wouldn't be able to do anything about it. I also get a little jealous of his girlfriend sometimes, because I want him by my side 24/7.Now to my problem: A couple months ago these minor gay thoughts just randomly popped up. By that I mean something like kissing him ect. And this strange love feeling appeared. I always loved him, but more like a brother. And I feel like it slightly changed. The thing is, even thinking about doing some gay stuff with any other dude disgusts me. And I started asking myself if it's possible to be gay but only for a single guy, all while still being into girls. I've googled my ass off for days but I didn't get any useful answers. After talking to him about it without getting any further, my feelings and thoughts eventually went back to normal. It stayed like that for quite some time. However some days ago these thoughts came back even stronger. And now I'm certain about what I want or at least want to try, but I'm sure he doesn't want to try these things. I don't want to confront him with this stuff anymore. Like mentioned above, he means the world to me, I can't imagine living without him and I'm afraid I'll fuck up our friendship if I keep bothering him. But I'm starting to get depressed, since I can't look him in the eyes or sit next to him anymore without creating a weird atmosphere, at least for myself. Something has to change but I don't know what to do anymore. I need some advice before I start going insane. I'm thankful for any answer.I also apologize for any misspellings or confusion. I've been up all night because this whole situation is fucking with my mind.And yes, I'm actually serious about this. And I'm new to reddit so to all trolls passing by: Save yourself some time, I won't give you any attention.