depo problems or something else??

Lilian

ive been on depo for about 3-4ish months and ive only gotten spotting very lightly a few days during the days that my period would be. but this month ive been spotting brown and red for about two weeks and my stomachs been hurting and ive been peeing more than normal. is this just the depo acting up or could it be something different?? please help.