Why did you continue to have sex when you clearly weren’t comfortable?
You answered your own question; you were tense and nervous and in order for sex to go smoothly you need to be relaxed. And no, bleeding after sex is NOT normal. It means he is just ramming it in there and hurting you. Please stop having sex if it’s uncomfortable.
The amount of sex you have really doesn’t matter, it doesn’t change the “size” of a vagina.
If you’re relaxed, use lube, do at least 30 minutes of foreplay on you and you still experience issues you need to see a doctor. In your case I would go to a different clinic/doctor as yours doesn’t seem to take you seriously.