I am experiencing irregular menstrual periods. i've had mine for 3 weeks, very light, and it's a brown, lumpy. i am due for my next depo shot 21 july?

Could be depopovera: Suggest pregnancy test to check depopovera hasn't failed but is a known effect of this treatment. Suggest seeing your doctor to discuss options and decide if you need any other tests (eg infection check blood count thyroid).

Depo & "periods": The use of Depo provera shots means that your menstrual "cycles" are at the mercy of the dosage of the medication, frequency of the shots, and its' ability to override your pituitary control. Brown lumpy periods are quite normal with Depo as it is induced withdrawal bleeding from the medication. Talk to the MD providing the medication about this answer.