Extremely long period

I need some help. Has this ever happened to you? I was put on the pill 4 days before my period. And it didn’t start on the day it was supposed to it started a couple days after and hasn’t stopped. I thought it extremely weird so my doctor switched me to the patch... I’m still bleeding. I’m on a 20 day period. Should I just stop my birth control? I’ve also been having sex so would it be a tear? Because around the 16th day it let up then I had sex and it started up again.