i have the same problem that u have. i only recive one shot. and i gain 10pounds in a period of 3 months so i decided not to use depo no more but i had the shot in march and in june i had to go and get the other one but i didnt but after a week i had a regular period and then i didnt have no spoting or period till mid july but it was not a regular one it was some spoting too. but sence then i havent had periods and i have done pregnecis test and there negative so i asume the depo is in my sistem and is not gone yet.