Question relating to weight

I’ve recently discovered I’m hypermobile. Always chalked things up to “I just overworked my muscles too hard.” Constantly brushing it off as muscle pain and fatigue.

I’m also pretty thin, not quite to a dramatic level, but definitely thin. 130lbs at 5’7, and my weight is slowly dwindling.

I have adhd and am prescribed a stimulant. Also have other chronic health issues that has given me an aversion to a lot of food.

I’m here to ask, what types of things can I do to help me gain a more sustainable weight for my poor joints..?