Implantation bleeding or AF?!?!

Ci
Hey guys I currently am in a situation of panic!
​I had my period last month on the 20th and I was checking daily if I was ovulating and testing with OPK I had supposedly ovulated on the 28th. 
​I found it real weird since that was 2-3 days after my period. Before I go further I need to say that I have PCOS with irregular and non existing periods at times. 
​Anyways, I woke up this morning and blood on my underwear. I was concerned since I have read implantation bleeding shouldn't be a lot.
​I heard implantation takes effect 10-14 days after you ovulate. and right now I'm having some crazyyyyy kind of cramps!! 
​What do you guys think?!