Check out the "sexual performance anxiety" program on this page.
Check out the audio talk linked in the article here:
Google "overcoming sexual performance anxiety" and feast on some of the articles you'll find. Sometimes reading about these things can cause a little bit of anxiety but that's pretty natural when confronting an uncomfortable issue.
I've had this issue with new partners and sometimes it reoccurs later on when the relationship is under pressure or intimate time is scarce. I've tried the pills and supps and have found them helpful from time to time, but they can also undermine me by allowing me to convince myself that there's something physically wrong with me when in fact it's all in my head. Lately I've opened up my current partner to an awareness of this issue by talking and sharing some articles. I find that this is helpful. With the issue out on the table and in the open I can start coming back to focusing on physical pleasure instead of living in my head.
Honestly the hypnosis download above for sexual performance anxiety, as well as the audio talk, have both been very helpful to me. I noticed they also had programs for sexual self image and other issues. Might be something to look into as well!
Good luck! It's a b*tch of a problem, but putting the work in is worth it. Also there's some truth to abusing porn and desensitizing yourself through 'rough handling'. If that's an issue you may want to consider taking a break from those things. Also look up supplementation with L-Arginine/Citrulline combined with Pycnogenol. If you have any minor problems with NO levels this combo can help and provide some extra oomph and self confidence. Just make sure if you try them to cycle them over time, don't stay on em daily without breaks over the course of weeks/months.