I’m on depo and I’ve gained

It’s been up and down I almost hit 150lbs and I’m only 16, 5’2 tall. I’m on the shot (depo) which I believe is causing my weight gain. I’ve tried counting my calories and it used to work really well but it hasn’t been now. I think when I go into junior year I’ll be more occupied with school work then eating when I’m bored or stressed. I’m also going to be starting to work out 2 times a day but I don’t think I’ll have time to workout when school starts. My school has stairs so that’s about the only time I’ll be “exercising”. Any other suggestions or things I could do when school starts. Things I could eat or drink? Any diet plans to try? I’d appreciate it