Hi Doctor

I am 24 year old and I had my first sex with a girl 1 day ago but I felt nothing during intercourse. I didn't feel any pleasure and my penis was not standing properly during sex. Is there any problem with me?
I was nervous during sex. I am completely dissatisfied and disappoint.
I used to masturbate before by watching porn, is that a reason?

Please explain me why this happen and what I need to do to get better sex experience.

Thank you

Sincerely,