Hi thanks for your question.
Irregular bleeding some time light and some time heavy along with vaginal discharge
is common side effect of Depot shot. It can even produce complete amenorrhea after 1 year of its use. What your experiencing is side effect of Depo shot. Body takes sometimes to adjust to hormonal changes when these side effects get settled. Abdominal cramps could be due to acid peptic disease
. For which you can take antacid and proton pump inhibitors like pantoprazole
. Depo shot can also produce stomach cramps
Hope this answers your question