I need help GAINING WEIGHT

Hey there ladies. I'm 19 years old and I've had trouble gaining weight since I was about 9. This past year (summer through winter), I finally reached 115 lbs consistently which was my (and my doctor's) goal because I am 5'7. But About two months ago I went through a stressful abusive breakup just before finals week at college. And of course I lost 10 lbs. before I ask my question you need some background: I am not anorexic, I do not have any sort of eating disorder. I do have ADHD and am medicated for that and a side effect is loss of appetite. I've been on this medication for years and it controls my disorder well and I gained weight successfully while I was on the medication before. I just get full very quickly, so I eat and then eat more two hours later or so. However, I am an extremely picky eater and I do not care much for meat other than poultry. I do snack through the day (I do not have time to have a full lunch during the day because of the nature of my work). If anyone can give me advice on some yummy snacks or foods that are somewhat healthy and could help me gain weight please let me know. I'm desperate. I don't know. I just need some help. ANY ADVICE PLEASE HELP. Or if you've gone through a similar situation please share with me