NEED URGENT HELP PLEASE!!!?

ok..so my period has been late by about 11 days, it's really never been normal until about 2 or 3 months ago where i started getting the 28/30 day cycle but ive been getting slight cramps like i already have my period...but ive only had sex once with a condom and it didnt break/slip or anything of the sort...im kind of really scared...will someone who knows what theyre talking about help me?