Late late late period but no sex? confused!

I'm about 2 and a half months late on my period and I haven't had sex at all! I'm really confused at this point, should I go see a gynecologist or wait and see if it's just a normal really late period? I have also been really nauseous and bloated, etc. I'm pretty sure it's impossible to get pregnant since I haven't had sex but my cousin had this boyfriend and he was very ... "weird" and "too nice" idk if he done something to me when I was asleep or not, I know that sounds crazy but I'm just so paranoid! someone help!