Normal?

I was on the depo shot for 6 months and I bled pretty much the whole time, I went off of it and suddenly stopped bleeding and then it started back up but it was just old blood for weeks and then suddenly nothing for months until today when I've had insane cramping and super heavy bleeding, I'm talking I bled through a super tampon in two hours and there's blood clots too which I haven't seen for awhile. Is this just my body adjusting to being off of it or what?