No Period After 3 Depo Shot!

I have had my first depo shot after i gave birth to my second baby, i decided to give it a break to go back to college. I had my first shot in may and my last was shot in Oct 2005, i have not had any spottings, or periods since. I have gained weight extensively, and i`m experiencing hair loss badly, i hate it, i wish i had never done it. Yes, i do get mood swings and my sex drive has changed, i hate my body weight and i can not stand the fact of being without a period for so long.