Pregnant?

So I had sex on my period during spring break and I’m pretty sure I’m not pregnant but two weeks after I had sex with this guy and he didn’t finish at all and...I was supposed to start my period yesterday so I’m a day late but I’m also very stressed about this and college work and worried about being pregnant like I’m 18 and I don’t want a kid and I’ve told both guys his and they are making me feel like a piece of crap. Also I’ve been cramping but no blood and I don’t know what to do