Birthday control changing flow

Shelby

So I’ve had a heavy period since the beginning. When I say heavy, I me like Niagara falls heavy (not exactly but you understand) and I’ve always had terrible cramps. It got to the point where I couldn’t move, I had to stay in one position to release the pain. So my mom took me to go get birth control. I’ve been on it about a month and now with me taking the last few pills in the pack, I got my period but this time it’s extremely heavy, I have cramps that seem to worse than the one before I got on the pill. Is that normal? For a period to worsen once put on the pill?