Just really confused

Hi all!

My body has been acting quite strange his month. I was almost positive that I would get my period this week because I started having my usual PMS symptoms last week (sore breasts, fatigue, and cramps.) Then two days before my period due date (the 13th) I started having some spotting which is very unusual for me.

My partner and I did have unprotected sex on the 1st, and my last period started on the 11th of July.

Now my question is if I should take a pregnancy test or if this ever happens to anyone else?