Why I am tired and never gaining weight?

[LIzBJ]

I just started school again and I've slowly been getting myself onto a normal sleep schedule. Yet, for some reason, no matter how much sleep I get, whether its 4 hours or 9 hours, I'm always tired. Always. I'm dozing off in class uncontrollably & I'm having trouble staying awake.
Back in April I lost over 12 pounds due to my bad diet/lack of food. I possibly suffered fr ARFID, which caused me to lose a lot of weight. I've been eating 2-3 meals a day now though, generally ham sandwiches, pasta, stuff like that, yet I've been stuck at 95-97 pounds for over 5 weeks now. I can never gain more than 3 pounds without losing it all by the next day. I eat a lot, I exercise some, but I rarely ever gain anything without losing it. This has never really happened before; just three months ago I was gaining a couple pounds a week and barely losing any of it, and now I can barely gain anything without losing it all! I'm unsure as to whether my weight problems and sleep are connected, and I'm getting confused and slightly worried and I have no idea what to do! Is it just stress, or is it a disorder of some sort?

[Red_Star]

If you are eating enough (I thought I was until I used fitness pal and found I was seriously undereating) you might want to have your thyroid labs tested for hyperthyroidism.