Hello, Thanks for sharing your health concern with us. I have gone through your query and would like to offer my opinion. Since you are stabilized on the depo shot, hormone imbalance cannot be the only cause for this recent spotting. You should also suspect any endometrial pathology, ovarian cysts, altered hepatic function and so on since such things can be a side effect of prolonged hormone use. I would recommend a sonogram of the pelvis, preferably through the trans-vaginal route to know the status of the pelvic organs apart from blood counts, urinalysis, coagulation and hepatic profiles in addition to a speculum examination. Further management can be planned accordingly. Wish you good health.