Hi Laura, I dont know how much help I will be but I will give it a shot. I have always been tiny and super athletic, working out around 6 times a week. I am 5' 1 but was always consitant around 98 lbs. I dropped to about 90 without even knowing it and it kind of freaked me out. I could see my bones and it was honestly gross, or at least in my eyes it was. In the begining of october I decided that i was going to try to put on weight healthly. I am happy to say that I have put on about 5 lbs. I am consitently putting on almost 1 lb a week. What I have been doing is this. Working out 6 days a week...3 days only about 15 minutes cardio and more weight lifting (builds muscle, and weighs more) and then 3 days a week longer cardio but still light lifting. I eat 5-6 times a day and have increased my portions. I eat 2-3 snacks plus 3 meals a day. I am IBS C, but by eating a little more it is helping me to go to the bathroom more consistenly and fully. My IBS is becoming more and more stable which is making it easier for me to eat a little more and add more of a variety to my diet. I am even begining to eat out a little, where I went about 6 months without eating out at all. I think not stressing about it is key. I know what needs to be done and I am doing it, not worrying helps. I am not sure if this helps you at all, but I want you to know that it is possible to gain the weight. If you want to talk more or go over daily food I would be more than happy to.