Spotting is quite normal for a couple of weeks maybe.. but 10 weeks? You should see your doctor about it. I was only spotting for about a week after my surgery and it was quite fresh clots. Yes tmi, but you asked!
My periods became quite irregular after my surgery, some periods were just 2 weeks of spotting, sometimes I spot between periods, so that could be part of your problem. I had my hormones and everything tested, nothing was found to be abnormal, but it is a reoccurring problem for me unfortunately.
I hope your doctor can help you, good luck.
It does sound like old blood and your body may be just clearing itself out, but I would talk to your doctor about it just be sure as soon as you can, if nothing else at least your mind will be at rest.