Confused on why I still don't have my period

I'm 16f and recovering from an AN relapse. I started recovery around 5 months ago, and have gained 10kg. I lost my period a year ago. Currently, I'm eating in a calorie surplus and although I don't weigh myself anymore I know that I'm gaining weight.

2 years ago I recovered for the first time and regained my period at a bmi of 15.5 (I also lost my period this time at around that bmi).

I am currently around 15.8 and have a high body fat percentage and I haven't been exercising in any way. Do I keep gaining weight? I've seen so many videos saying that if you've gained the weight and your period isn't there, it may not be a weight problem. Advice appreciated!!