gained 10 pounds in a week from DEPO Shot

You guys, I have been doing so well for about 7 months with losing weight and getting fit for college, I went from 180 pounds to 140 in just six months. But my gyno recommended the DEPO shot for me because my periods are so horrible and I have PCOS. But I’ve gained ten pounds since Monday and I don’t know what to do. All I want to do is eat and eat and eat and not workout. Does anyone have any advice when it comes to beating the weight gain side effect from birth control?