Weight gain with depo

I'm at a complete loss. 
I went to put my shorts on from last year and they don't even button. I look so big from last year. I was on depo for 8 months and gained so much. I'm trying so hard to loose it. There was a point that I ran 5 miles a day cut calories no junk and trained at the gym and haven't lost a pound. Has anyone had this experience? How do I lose this weight 😭😭