<human>: Okay, so I'm 24 and I've been in a relationship for the past five years. Best sex I've ever had. I had a long term relationship before this and also had continuous sex. I've never had an issue getting going and then out of the blue I couldn't get started a few weeks ago with my gf. I had no idea what was going on. I thought I was just stressed form work. We take a five minute break and I'm good to go, it was quick but it was fine. 

A week later, we're fooling around after a night of drinking and i'm feeling back to my old self, but it's that time of the month so i settle for a bj. When she's off her period we set up a day to get together and have sex because we both need it. I build it up so much in my head that again I can't get going. I sit there embarrassed feeling awful again for about five more minutes and then I'm able to get up and we have sex. 

Ever since that time I haven't been able to stop thinking about it and it's driving me absolutely crazy. I'm terrified that it's going to happen again, but I know that if I keep obsessing over it then it will in fact happen again.

I'm in perfect health. I've been taking l-arginine supplements to increase blood flow (have slightly high blood pressure). I exercise daily and have started meditating and doing yoga. I'm fine when I watch porn and I can jerk off on my own without porn. 

I would really appreciate any advice that anyone may have about this because it, obviously, has freaked me out and I need to get over it. I'm an anxious person by nature and that has exacerbated this for sure. Help?

Can you summarize the given text in a few sentences?
<bot>: long term relationship with the girl of my dreams and after five years of sex i'm suddenly having trouble getting going because of my obsessive mind