I just had sex for the first time..

I had sex but it was hurting and I don’t think he fully went all the way in. How do I know if he did? Somebody said I would hear a pop? But I was bleeding after the fact, unless unprotected but he said he didn’t go inside me, and I don’t feel like I should just trust him on that, should I take a plan B? If so which one do you suggest and does it mess with my period, if I take it today and my period is due in 13 days??