I have cellulitis infection on tip of left buttocks. i have been on meds for 2 days now and it wont stop bleeding. how serious is this?

Depends: Abscess are best opened and drained. Sometime nature helps out by letting the abscess pop spontaneously and drain. If your cellulitis was actually a developing abscess then drainage is expected. A steady flow of blood isn't. If the drainage is a mix of pus and blood then keep clean and bandaged. If the bandage continually soaks thru call your doctor.