Let me second what Tracey is saying. I learned what yo-yo dieting meant, and what it does, by doing it. I worried about my weight from the age of 10 on, and while I'd lose all the weight in the early years, as time went by, each time I gained it back, I gained more until I landed where I was 2 years ago. It was deeply frightening, and I was getting too close to being disabled.
I wish with all my heart, that I had made a permanent change the last time I lost all the weight (back when I was 30). There are things I now can not change, can not fix, I must deal with what is *now*, but if I had a choice, I'd never have chosen this.
Value taking care of your health, including your weight, and make any changes needed now. Do any learning about how you use food, why you eat what and when you eat, *now*, and work it out.
You *can* do it, there is a lot of wisdom on this board