I get super hard when there’s no expectations

Was visiting my gf this week and was super confident in myself the weeks prior, our sex life is usually very good, and I would get hard just thinking about her, seeing her or even when she would look at me in a certain way, but as the day started to draw nearer I started to lose that confidence, I started to think “will I be able to satisfy her?”, “is my penis going to work?” As soon as I got to her we started making out and getting into things, all the while I was thinking about those doubts. In the end it went rather well. Even though it went well I still have this anxious feeling like I’m not good enough or I can’t perform.
This morning after a good week of sex and no sex (she got her period and prefers to not do it the initial few days) we wake up and we’re cuddling in bed and I get hard, so she goes to take her cup out, when she comes back I have a weak erection so she starts to grind on me which usually solves the problem. We’re having sex and then when I’m near the end I tell her to get a condom and put it on me… as soon as she starts to put it on I lose it. This really kills my self confidence. I hope this app can help.