I've been spotting since i received my last depo-provera shot almost 3 months ago.i've been on the shot for almost three years..is this normal?

Depo bleeding: Bleeding on depoprovera is highly variable. There is no normal time for your period on this birth control method. Most have no periods. Some have irregular bleeding. Irregular bleeding can be annoying but it does not mean that the method is not working. This side effect is very typical of Progesterone only birth control methods.

Common side effect: One of the most common side effects we see from Depo injections is irregular periods, which can range from varying cycle lengths, to very heavy or very light periods, random spotting, or no bleeding at all. Depo is an effective contraceptive but there is still a chance for pregnancy. I would rule that out. Also, with your long term use, be aware your bone mineral density can decrease drastically.