Gastritis, IBS, and motility problems after gallbladder sugery

I am 18 and for three years I have had ongoing digestive issues and last year, after several tests, the doctors came to the conclusion that my gallbladder wasn't functioning as it should be. He told me that removal helps with 70% of patients, and that I would most likely get better. But, the opposite has happened. I have only gotten worse. I can't really eat anything, or it will make me throw up or have really bad stomach pain. I feel nauseated quite a bit. After my gallbladder problems I was diagnosed with IBS. My doctor put me on Librax to help with that, but now I was recently diagnosed with gastritis, and I had to be put on a liquid medicine to help slow down the emptying of food into my stomach. My doctor said that since my gallbladder is gone, that bile is constantly being dumped into my stomach, which causes the gastritis. I'm also losing quite a bit of weight because of all of these problems. What kind of foods should I eat to help with these conditions?