How do I feel better about myself?

I've been with other girls that I felt eh about and had no problem. But of course, my luck. One of the nicest most gentle/caring people I've ever met, I can't get it up.

I was so fucking nervous and I don't even know why. Was it the pressure of wanting to please her? She was super comforting about it and said it's not an issue.

I obviously then helped her in other ways and she enjoyed it. But I cant help but feel so shit about myself.

Any advice to not hate myself and feel like I fucked up? I try and tell myself that the right person wouldn't think different of you for something like that. But that doesn't really fix anything. Fml

EDIT: I appreciate everyone's kind words, it means a lot to me that I'm not alone and not made to feel humiliated about it. It really has made me feel a bit better.