I've Been Having My Period Every Two Weeks They Found

I've been having my period every two weeks they found a cyst on my ovary but said that's not the cause my blood work came back normal I having had a pap yet because I'm always bleeding they gave me the seven day pill to make it stop but now I'm bleeding again but this time it's really dark brown the only pain I have is in my lower back should I go to the emergency room tomorrow? Thank you!