weird movements and guttering and getting lowerback pain (also vomiting and frequent urination)

Hi for over the past three onths i have been gettin really bad pain in my lower abdomen and weird movements and guttering and getting lowerback pain (also vomiting and frequent urination) and with the both its making it hard for me to stand up straight, i am also getting out ofcontrol mood swings and go dizzy stnding up. i am on the depo provera injection but was like this before i had my first injection i was getting very heavy bleeding nowhere near my period dat and i have had 4 pregnancy tests all negative, the doctor has tested me for STD's negative, water infection, negative im unsure whats wrong with me and getting worred. my beeding got much worse as i have came abroad to visit family and when the plane took off i was coverd in blood. if anyone can give ma a clue as to what wrong that would be great! :D