@wildcat212,
A) Drink less before you're going to have sex. It degrades performance anyway, and apparently it increases your anxiety spiral.
B) Try having sex with women you know better, versus just the hottest girl you can get for a quick one. As, date for a while before hitting the sack. You clearly aren't, if you're garnering 3 partners in a span of no more than 6 - 8 months. Hanging around with someone, and knowing them a lot better, tends to decrease initial performance issues, mainly because there isn't quite as much riding on it.
C) Consider talking to a professional about this, as you alluded to. If it bothers you, talk it out.