Hello, I Just Stopped Using Birth Control About 2 Weeks

Hello,
I just stopped using birth control about 2 weeks ago and I had my period. However, I've seen to have gotten my period again yesterday and its a lot heavier and clotty than it has been when I was taking the birth control pills. This seems to be a recurring thing every time I stop taking birth control. Almost like a menstrual rebound. Sometimes, not to be graphic, the flow doesn't come out on its own. I have to use the bathroom and then there's a bowl full of blood clots and nothing on my pad/tampon. Also on Friday I took a Plan B pill. Lastly, when I was on the nuva ring I didn't seem to have any of these issues. Could it be a dosage problem? thanks!