I'm a very lucky man. I met a wonderful woman a couple months back, and now I'm trying to take this situation somewhere wonderful. The on-topic stuff: I wound up in bed with this wonderful woman, and throughout the course of the evening discovered something that upset me incredibly. Try as best I could, I couldn't keep a hard on for more than five minutes. I did some thinking over the next day, and realized what had changed recently. I'd been prescribed Celexa a few weeks prior. I'm off it now, but... It took a disturbingly long time to get back to normal. Anybody been through something like this before? What the hell should I do? She didn't mind. Matter of fact I was told her exact words when replying to "So, did you have fun?" were "Wow... Just, wow..." and not in the "OH MY GOD IT WAS HORRIBLE!" way, in the "Uh, that's all I can manage to say..." way. I'm guessing I should just not worry about it, but for some reason I look back on that with "Damn! Of all possible times, why then? Why?! When I'm in the mood to have fun and amaze, why?"
See if you can switch your medication to something that doesn't give you that side effect. That's the only advice I can really give you. I haven't had this problem but I know it would suck.