I Thought I Was On My Period Because I Was

I thought i was on my period because i was spotting. There is only blood when I wipe though, nothing in the toilet or liner. I am a diabetic, and i'm on metformin and synthroid. I also started taking the pill the day i started spotting, thinking it was my period. That was last tuesday, and i'm still spotting. I also had polyp removal surgery in June, but my july period was normal. what's going on?