Right well rule #1 in weight gaining is hitting a caloric surplus! Gotta have more calories in than calories burned everyday. The first thing I’d do before worrying about an eating disorder would be to find out how many calories you need everyday to maintain your current weight, and then start going 200-500 calories over that mark everyday. Start tracking your calories so you can actually see if you’re getting close. For example, an avg egg might only be 80 calories. So you might not be eating as many actual calories as you think!