um... HELP!

I had unprotected sex a day before my periodnwas due to start. my partner did not ejaculate in me, he didnt cum at all during that night. my period is now late by three days & Ive been having tons of white creamy discharge. I was also thinking that (besides pregnancy) the reason why my period is late is because Ive become sexually active for the first time in a while in the oast month? can sex change your cycle? Am I pregnant? HELP ME PLEASE