If you plan on not having kids in at least 3 years is good.. If not dont do it... it gets your period crazy and then its hard to get pregnant... Thats whats happening to me...
I would think about it and be sure. People have experienced bad weight gain, heavy bleeding or spotting, etc. while on the shot, though some haven't. Whereas you can stop a pill or any other hormonal method if it starts causing problems, the injected hormones will stay with you until it's time for your next shot, so you will have to endure side effects until it wears off.
My weight went crazy too.. I went from 125 lb to 185 lb... Thats why I only used it one tine.. And i hate it...