Male, 18, virgin. Almost had sex tonight but couldn't get a full erection, and even then it would only last for a minute at most.

I know its psychological, because I can get hard just fine any other time. Ever since discovering TRP, I've cut down significantly on porn and masturbating, to about once a week. Still, even though I was in bed with a woman I was attracted to, I couldn't get it up. The harder I tried, the more frustrated I became. Any ideas on what the problem is? How do I make sure this doesn't happen again?