A penis with semen touched my vulva and it was the last day of my period. Took morning after pills the next day but I'm paranoid that I might be preg.

Pregnancy? Contact with semen is always a risk for pregnancy, but if this was the only contact, and it was on the last day of your period, the chance for pregnancy is very low. If your period is delayed, get a serum HCG test, which is much more accurate than "home tests". .