may be you have started your periods,not with your boy friend entering you.next time ask your boy friend to enter gently using a lubricant and not in hurry, surely with a condom.
sounds like you are starting your sexual active life. please educate yourself on birth / pregnancy management (how to prevent it) and also make sure that your boy friend is tested for STDs before you start having sex with him.
Hello.
I don't know why either. This is a question for the Gynecology Expert Forum at:
http://www.medhelp.org/forums/show/103