What Causes Stomach Pain, Constipation With Blood In Urination?

hi i need to know what is going on with me ... i am on this birth control called depo Pravda and my last shot was Feb . i take it every 3 months . i don't have a period any more i only have spotting on the day im supposed to have my period. and that was last week. well the last couple of months i have been having a lot of stomach pains and the doctors don't know what it is. but for the past couple of days i have been peeing blood. i haven't had an appetite. Ive been tired , constipated. and now im always hungry, always tired Ive been having head aches, constipated,and peeing blood, im sniffy.