your not gay or even bi-sexual. i am in the same situation right now i am a guy, the place i use to work all the girls want me to date them but i vow not to, then the started saying thinks like he might be gay and guess what it freaked me out thne at a point i start to realise that i have hocd.one quation you will ask your salf who do you wanna spend your rest of your life with male or female.
I would bet money that you are as straight as they come, but you say you "would not be able to survive if you were bi". Why not? It won't hurt you. No one's ever died from being bisexual. So what if you are? If anyone else doesn't like it that's their problem. The reason I say this is because the "wouldn't be able to survive" is the kind of thinking that will fuel your fears. You gotta allow yourself to have these thoughts and be ok with them if you want them to stop. Tell yourself "so what if I'm gay", or "i know I'm not gay, it's just a normal thought that everyone has". Even if this makes you uncomfortable at first, the more you say it to yourself, the easier it will be. Since you are allowing the thoughts to happen and reassuring yourself it's ok to have them, they won't seem like such a big deal and won't happen so frequently. This worked for me with a fear I've had, I just used different phrases. I highly doubt anyone around you thinks you are gay. You haven't given anyone a reason to think you are. Again self talk may help this. "So what if everyone thinks I'm gay, I know I'm not. They still like me because they still hang out with me so it doesn't matter. If they didn't like me because of that they aren't worth my time anyway."
I am bisexual. At NO time did I ever fear being bi/gay, nor did I realize I was because someone mentioned it. I realized it because I am attracted to women and men, not cuz someone said "are you bi". I'm married now to a man, so I don't seek women (or men for that matter) anymore as I am faithful to my husband, but I realized my sexual orientation very young. Everyone is different, so I can't speak for anyone else, but none of my friends ever had these ocd-like symptoms when they realized they were bi/gay. I hope this helps, but we're not doctors and you should really talk to a therapist, they can help you get rid of all this fear.