Period or implantation bleeding?

So ladies, I had my period last month on the 4th and I started taking birth control pills on the 5th. I stopped taking the birth control pills around the 12th because they started to make me very sick. Once I stopped I got my period. My period lasted till about the 16th. I had unprotected sex on the 30th. Now I am late for my period and had spotting. I feel a little nausea after every time I eat. Does this sound like pregnancy to you or PMS?