Weight gain

Basically, for the past 8m-1yr I’ve put on about 40ish pounds. Try not to touch the scale bc it’ll send me honestly. I’ve got my thyroid hormones checked, normal which is good news. Which leads me to thinking it’s my birth control. I’ve been on nexplanon for the past 4 years. Never had much problem other than the occasional break through bleeding. It never altered my weight if anything it made me loose some. With the break through bleeding they had me on the pills and nexplanon?? Than switched to the Nuva ring. I’m 19 I’m healthy I work in health care; non stop and go to the gym. I’m doing everything “ right” my doctors aren’t seeming to help and I feel like a lost cause. Granted I’m not 15/16 anymore but I’ve never had any other problems.