Post Bulimia Digestive Problems

Hello, I've have bulimia since I was 12. I'm 22 now and just got help last September. i have been doing so much better. Only a few relapses. The residential treatment program I went to in Sept. taught me to eat 6 smalls meals a day. Variety, Moderation and Balance. I have been doing that. But for the past 3 months my stools have not been solid. They've been green diahrea. Yuck. Also when I have gas it hurts really bad and takes a long time to get out of my system. Are these problems associated with the disorder I had for so long? Or could I have parasite? I try herbs to get rid of the gas, but they don't work thoroughly and as quick as i'd like. Can you recommend something? Should I change my diet? Only eating certain things. I'm nervous about doing that, but what if I have a food allergy or something. Any help will be greatly appreciated. Thank you.