Ive been on my period for almost a whole month and ive been gaining alot of weight lately and i am on the depo shot so i want to know if its normal?

Longer "period": This type of bleeding is probably not a "period", but represents a constant breakdown of uterine lining, which causes spotting to constant flow. Depoprovera is just progesterone, and ovulation typically may be prevented, in which case estrogen production leads to an increase in the thickness of the uterine lining, which on breakdown, causes this sort of event. See your gyn provider for an exam.