I have ibs as well. I am not bulimic (although I have purged a few times before), but I do exhibit many signs of anorexia. That's partly due to my adderall addiction and partly to a body image problem.
I know that when I starve myself and then a day later eat a small dinner my stomach doesn't know how to handle the food and I usually get very nauseous or get an ibs attack.
For you though, it is absolutely clear that your stomach is traumatized from the bulimia. When you throw up your food on a constant basis, the acid in your stomach overdevelops and burns through the lining of your stomach and throwing the chemical composition of the acid out of whack. Also, now that you've stopped purging (good for you by the way) your stomach's is not used to normally digesting food, and it begins contracting and you get an attack. You probably have acid reflex and heartburn as well.
I think it is crucial for you to tell your doctor about the bulimia. I understand its a difficult thing to talk about, but she would be able to help you get rid of ibs symptoms, or at least make them less harsh. The point of ibs is that its so individual that doctors often suggest you keep a diary of food you eat and when the attacks occur so you can track the main food "culprits" that your stomach cannot handle. Otherwise there is little they can do to help you. But if a 6-month bulimic episode is brought into the picture, your doctor will probably tell you that it may not be common ibs, but specifically bulimia-induced ibs.
So please, please, please tell your doc. They are sworn to confidentiality so you don't have to worry about that. And if you didn't tell her b/c you're embarassed, trust me- she has heard and seen much worse. Do this for your own sake and health, and good luck to you.
