Okay So I Haven't Had My Period, Although I'm Pretty

Okay so I haven't had my period, although I'm pretty sure I was spotting so I thought I was getting it, my ex recently broke up with me so I also thought it could've been stress from that, although I had unprotected sex last night... The boy didn't finish.. Haha everything was fine but when I got back to my room I noticed a decent amount of blood on my undies, thought the sex could've brought on my period but I don't have it? And today my lower abdomin it paining