Hopefully it's just spotting? Like y-pod said, I don't think you would have ovulated while you had it in. Also, if you do start going through regular cycles again, it might take a few of them before your body adjusts to the change in hormones, so whatever happens the first time may not necessarily be the new normal. I hope anyway.
I'm glad the removal wasn't too bad. I remember when I had mine taken out it wasn't painful at all, but that might have been just because I was so happy to get rid it. I had one of the copper ones because progestins mess with a connective tissue disorder I have, as well as my mental health. For me personally the copper one wasn't great either, though. Loved that it was hormone free, so I just sort of put up with it for several years, but I was anemic no matter what I did due to the heavy bleeding it caused and it cramps could be horrific.