Pregnant or stress :(

Hey all I really need some help right now.

I had sex two months ago and it was on one of the fertile days after my period had ended that month and it was also unprotected (he pulled out). I got my period last month and it was regular, everything was normal. I’m currently going through a lot of stress because I have exams going on and I’ve been under this stress since about the end of last month. My period was due 3 days ago and there’s no sign of it yet, which is making me even more stressed. I’m so confused now, could it be that I’m pregnant? Or is my stress making my period late? Please help!