Nervous.

I'm such a paranoid person. I lost my virginity and I do sort of regret it even though it was with someone I really love. He literally went in once and it hurt so bad but I'm so paranoid and anxious that I'm making myself think I'm pregnant, I'm literally just getting period symptoms because my period is supposed to come in a few days. What do you think I should do? Am I just freaking myself out or does it mean I'm not mentally ready to have sex again.