I am so sorry you and your baby has been through all that. Hopefully they have found the problem and now you will be able to get your baby feeling better.
My Rosie has IBS. We had problems with vomiting and diarrhea before she was diagnosed. We had a few scares before she was officially diagnosed. It is something that can be controlled. The best thing I have found to control it is through her diet. I currently home cook for her as I have found it to be the best thing for Rosie. I used Petdiets.com to get the recipe. I can honestly say that we have not had near as many problems since I started home cooking. Before I started home cooking, she was on Science Diet I/D. The Science Diet did a good job too but I think the home cooking has been better for my Rosie. If I can help in any way please let me know. Feel free to pm me.