Depo shot /weight gain/getting pregnant

Okay ladies so this coming May I take my 3rd depo shot . Lately depo has been turning my body and my emotions for the worst I just started bleeding heavy and my emotions are all over the place. Another thing is I gained so much weight on it . I used to be in the 130’s now I’m in the 150’s no matter how much a work out to lose the weight it doesn’t help.any suggestions? Also My fiancé and I want to have kids soon but not too too soon so do you think I should stop taking it so I could have a better chance ?