For the gas, have you tried Mylecon? The actual drug name is Simethicone. It works REALLY well for alot of people.
Since you're bf, you can put it directly in his mouth, and that should help gas problems rather quickly!
It's not harmful for the baby either, since it doesn't get absorbed by their body, it passes through.
I've not bf, but we do have a long history of allergies in my family. Keep your journal for a few days of everything you eat, and then start picking it apart for the "usual" suspects, I.E., dairy, citrus, soy, wheat, etc.
Eliminate one at a time, and see if that helps your lo!
HTH!