Anxiety and Sex Problems

So i am a 21 year gay guy and I have general social anxiety issues as well as OCD and off and on depression. I have been sexually active for a pretty long time but each time I have sex either with someone I'm dating or a hookup my issues get worse and worse. Up until I was maybe 16 or 17 I was always the type who was easily aroused even just at hugging a cute guy or cuddling would sometimes give me an erection. But then one day when I was 17 I hung out with a guy who i thought was straight but ended up being bisexual and convinced me to do stuff with him even though I didnt really want too. I wasn't really into it and had trouble staying hard even though he was attractive. We continued hooking up every once and a while and every time it was a struggle for me to stay/get erect. Ever since that happened its almost impossible for me to get hard with another guy even if we have been dating and I'm comfortable with them. I know its not a medical problem because I can get an erection no problem when I masturbate or am horny but as soon as I'm naked with another guy all I can think about is how I wont be able to get hard and then they spend a long time trying to get me hard until we eventually give up and do other sexual stuff that doesnt require me to be hard. Typically what happens is we will be hugging, cuddling, making out etc. and I will be hard but as soon as the pants come off I completely lose it. I know I could ask my doctor for pills but I am only 21 and dont like taking medications if I dont have too. Does anyone else suffer with this problem? Help?