20 year old never had period

Katiemarie
I am 20 year old and never had a period. Wednesday after sex when I woke up there was heavy blood clots and blood in my urine. I don't know if it's my period or something else serious since I've never had a period before.. It's going on 3 days now with heavy bleeding, cramps, sore nipples, and I've been bleeding through my clothes.