Signs of PMS or early pregnancy

I have a very irregular cycle as have PCOS... I had my last period on the 28th August until 6th September. We have had unprotected sex on September the 16th, 18th and 23rd. I was getting pain in my left side from September the 16th until the 20th. I then had spotting on the 29th and today and quite bad aches in my lower back. Is this just PMS or possible signs of pregnancy?

Sorry about the pictures, the first picture is yesterday. The other is today.