IBD? Need help.

Hello. My name is Fer.
I have colitis. I don't know much about it. I do know it's not ulcerative colitis and I think it's not Crohn's, but I don't know which type I have and I don't really know what I should eat.
I went with a doctor and she gave me meds for a bout a moth (lansoprazole, trimebutine and zimeton) then took away zimeton and trimebutine and add pantoprazole and some natural guayaba pills.
I had excruciating pain, very much like menstrual cramps, but so strong that I would cry. I was constipated and then had very bad diarrhea and then constipated again in a lapse of a couple of hours. Lost a lot of weight.
I have a crazy fast metabolism and I was having trouble staying at a healthy weight level without colitis. Now I'm skinnier than what would be the healthy limit and unable tu put extra weight on. I started eating only chicken, vegetables, turkey breast and apples, without any condiment whatsoever. I've been adding more and more over the past few months. I was feeling a lot better. Actually now I'm inflamed again because I was testing to see what I can eat now.
No eggs, no tomatoes and no beans. Nothing that's fried obviously. Not popcorns either and no whole dairy products.
I'm fine whit jam, lean red meat, ketchup, bananas, nuts, greek yogurth and even coffee (just a cup every few days).
But I want to know what else can I eat to put on the extra weight that I need. I tried driking a protein milkshake after my workout session, but I had a horrible pain after that.
I need advice.
Thanks!
Good day.

Thanks, I'm going to try the powder weight gainer.
I've been trying almond milk and it hasn't affected me. Maybe you should try it too.
People always say how lucky I am to have fast metabolism and it has its perks, but most people don't know the struggle that is to gain weight.

Thanks. I will go to my doctor again and I'm also going to have a chemical test, just to make sure I don't also have some kind of anemia.
I already made an appointment with a nutritionist. I'll share the tips she gives me with you just in case they can help you too.
;)

Sorry they called you that. Yeah, people is ignorant sometimes. Before my dad finally wrapped his head around my fast metabolism and colitis, he used to proclaim I was skinny because I simply didn't wanted to eat. He's nice now though, so no harm made. But still...
Yeah, life has a... let's call it "funny" sense of humor. My biggest passion used to be food. My brother once asked me if I prefer to have a stomach bug or the flu, and I said the flu because at least I could eat whatever I wanted and be happy. And now I can't eat half the things I love.