I had a d&c w/uterine biopsy 4 days ago. tonight, still cramping, more light bleeding and red tissue coming out. what gives? why does this happen? this wasnt told to me before the procedure but told i could bleed for 10 days. im angry over this?

The red tissue could be clots and part of the bleeding. Depending on the reason for D&C, you could have bleeding and "red tissue" for the time your doctor warned you about bleeding. If you the bleeding is subsiding and you do not have other symptoms, you could watch and wait. If the bleeding gets worse, you get fever, a purulent discharge or excessive pain, it would prudent to see your doctor.