Am I pregnant?

ok so I have pcos and very rarely have two periods back to back. my last one started on November 1st and lasted til the 5th. I had sex on the 15th. Well I had VERY light bleeding on the 28th for only a couple hours. nothing on the 29th but today on the 30th, I had heavy bright red blood with small clots. I know implantation bleeding can occur 3-7 days before your period so light bleeding on the 28th would make sense. However, I'm not sure why it stopped then got heavy two days later. im having a pulling feeling in my abdomen and a pain in my lower right rib areas, along with headaches and taste bud problems. Everything I eat and drink leaves a terrible taste in my mouth. Any idea what's going on? Is my period just early and actually coming back to back or am I pregnant?