Sex with new partner?

im slightly worried, i've recently started having sex with my new boyfriend, my ex was my only other sexual partner which was over 2 months ago, however my new partner is a lot larger, after sex i experienced slight bleeding, and am now feeling a bit tender like i did after the first time i had sex, this has never happened before, however the blood was gone after being to the bathroom, we have both been tested for STD's previously so i know it cannot be this, i am not due on my period for another 4 or 5 days (i am on birth control) could this just be because he is larger than i am used to and i have not had any sexual encounters for a while? i also skipped my period last month as i was on holiday could this have affected it?