Welcome Marina, your English is very good so don't worry. Congratulations on all the weightloss, that's a lot of weight to lose on IE, I've only managed 10lbs since February.
I know a couple of people who have a sensitive GI tract, a friend who seems to suffer in the same way you do and my husband who doesn't suffer often and when he does it's due to eating too much of one thing and not enough fresh veggies. Most of the time his troubles stem from not drinking enough water so I have to chase him around with glasses full of water for a few days until he gets better.
"No matter how developed you are in any other area of your life, no matter what you say you believe, no matter how sophisticated or enlightened you think you are, how you eat tells all." - Geneen Roth