Help. Need Some Answers 👀😔

Sooooo I Been On My Birth Control For Maybe 3 Weeks Now I Started Taking It At The End Of March. I Usually Get My Period On The 8th Of Every Month. It Last 5 Days. I Was Still Taking My Pills The Week Of My Period I Experienced Light Spotting & It Went Away. But On The 12th My Period Came Heavy! It Is Not April 18th Six Days Later I'm Still On My Period. Whats Going On? & I'm Also Cramping Worse & Bleeding More Heavier Than Ever. 😷😢