Spotting two days before my period!!

I had unprotected sex on the 13th (which was Day 21 in my cycle). On the 20th (yesterday) I got a bit of spotting so now I’m terrified that I might be pregnant. Can you guys help me out? I’m supposed to be getting my period in 1-2 days. I’m already experiencing period related symptoms but I’m scared they could be something else... please help!