Heavy Implantation Bleeding or AF??

Karen
I have PCOS and almost never have a period or ovulate which is super frustrating because we're trying for our first baby. When I do get my periods they typically start out slow and then on day 2 or 3 I start getting clots that slows down by day 4-5 and completely stops by day 6. My cramps are also usually debilitating to the point where the couch and heating pad become my best friends and I live off ibuprofen.  
Lucky for me I FINALLY ovulated 5/10 so I am currently 12 DPO. I had some mild cramping this morning but I didn't need ibuprofen and within 30 minutes I had some pretty average bleeding but with blood clots. I thought for sure my period had started and was just a little heavier than normal for CD1. But it's been about 8-10 hours and the bleeding has almost stopped and the cramps have been nearly non-existent. 
I never know what to expect with PCOS so I'm wondering ... Could this be my implantation bleeding? I've read a ton of articles and I know it should only be light spotting and be dark brown or light pink, but my bleeding today has been less than ordinary (even for me). Has anyone else had heavy implantation bleeding or IB that started 12 DPO or later? If I'm not pregnant I need to take Clomid in 2 days. Thanks!!