Newbie to BC: Please read asap !!

So basically I have been on birth control for about 8 days now, meaning I started on last Sunday on Valentine’s Day which was the 5th day of my period and didn’t do anything until early this morning at 6am unprotected. Now my partner did slightly pull out too slow and came in me and I immediately peed and wiped myself right after. I’m only hesitant about the Plan B because it will be my first as well as I don’t want the heavy bleeding or anything. What is y’all’s opinions on what I should do?