Confused. TMI

So I am 7DPO and I got a positive opk, I also had a cramp and went to the bathroom and had a little bit of red blood on my underwear and the toilet paper. Now it's just a very light pink. I'm suppose to start the pill but I don't know if this is AF or what! I'm not suppose to get AF until the 6th of October. Should I assume this is AF and start the pill tomorrow? Thank for your help!