Thanks for posting this topic and thanks all for sharing.
This is an issue that I have struggled with since my diagnosis at age 11. At that point I'd already reached my full height - 5'8" (I come from a tall family) and I weighed about 90 pounds. I ate and ate, but never kept any weight on. Once I was diagnosed with Crohn's the first thing the doctor said was, "well, now we can finally get some weight on you!!" and I was terrified! All the girls in my class told me I was so lucky to be thin, and I thought that was the only reason they liked me. I was also so scared of getting a big moon-y face from the prednisone. My GI doc said that limiting my salt intake might help with the moon face, so I became obsessed with all the sodium in food and started measuring all my portions and working out for 3-4 hours every night (my dad had a home gym in the basement and I would sneak down while my parent's watched TV.) One of the GI nurses noticed that I was gaining weight, but not as much as they would have liked and she asked me about it. I confessed about the exercising and measuring the food. It was a huge burden off my shoulders to have the secret out and to get positive support (I went to a therapist for a short while at that point.)
Flash forward to my last big flare up 6 years ago - I weighed a pretty healthy 140 at the time and was feeling good - when all of a sudden I was hit with a huge flare. I was on disability for over a month and threw up almost everything I ate. By the time I was approved for, and on, Remicade, I weighed about 115. Once I started on the Remicade, I started gaining weight, but it was slow going and took about a year before I got to 130, which is where my weight has pretty much stayed.
There are some days when I still feel big. I'll weigh myself and think, hmmm, if I got down to 120 this might look better, or that might be slimmer. I always feel a bit defensive when doctor's mention a weight change, or make a comment about it - good or bad. I feel awful about that. I KNOW that my weight is healthy, but I've been on a very restricted diet for the past year and think, why haven't I lost more weight? At the same time thinking, that's crazy! You need the extra weight in case you get sick. I feel like it is petty of me sometimes, there are so many other problems I could have - and that others have - why is my weight an issue? But it is hard when people comment about your weight and seem to expect you to look a certain way.
Sorry for the long ramble, I just couldn't stop on that one! I really just wanted to say that you are not alone and that you should not feel guilty about gaining the weight. It is totally normal - and healthy - to gain weight back rapidly after a flare. Your body knows you need it right now and it is good to keep some extra pounds on to be healthy - and just in case you do have another flare. Give yourself more time to recover and get 100% better and then there is always time after that to go to the gym or worry about calories. And despite my ramble above, I do feel that way and have not been counting any calories or restricting myself this holiday season!! Plus - I never get to decide where the weight comes off of - and a decrease in weight usually equals a decrease in chest size for me - and I don't have much to spare!