Stress or pregnant?

So I had unprotected sex with my boyfriend about 2 weeks ago on the 8th. My last period day was the 26th of February. He pulled out before he came. But I know that men can preejaculate. My period was supposed to start as calculated 2 days ago. I started having abdominal pain and 2-3x that I have gone to pee,  I have spotted just a little bit  like when you're about to start your period . Has anyone else had these symptoms? Could it be stress causing it? I' usually get acne when I'm about to start my period and I got it 2 days ago. Please comment your experience and thoughts