Depo Don`t Do It...?

I am a woman in her mid-forties, have taken Depo off & on for 10 yrs. I have grown children and do not want to become pregnant! But I am also older and smarter and don`t want to have sex with someone unless they are truly someone I will want so spend my life with: Due to that I have less sex, and only took the shot once this year for protection (3months) which unfortunatley the relationship didn`t last..but I didn`t get another shot. Since I didn`t get another shot, I have not had a period and the weight gain was NEVER a problem while on the shot--but, EVERYTIME I get off the shot I gain and this time its the Most ever(10 lbs, and I am very weight consious so this makes me MAD!)I exercise EVERYDAY but it has felt like I am pregnant appetite wise and I am really wondering if the shot is the cause(*Or lack therof!!)Any body else had it happen this way?
Angela9-1-06