Why is my period SOOO Heavy!?

So i got my period yesterday then during the night it got REALLY Heavy like if i went to go pee i would bleed and when i went to sleep and woke up this morning I Had on a Super Heavy Always Pad & Itwas long too wl wings and i had blood alll the way in the back. Im still bleeding super heavy and if you could tell me whats wrong great. Thank You So Much!!!