For us it was dairy and soya, I cut out both at once but reintroducing either gave us symptoms similar to what you describe.
The "big four" of intolerances are milk, egg, wheat and soya, you'll see people refer to MEWS free diets. Some babies react to more than those, and there is a limit to what you can cut out. I did dairy/soya free for over a year and I don't think I could have cut out anything else longterm - that would have been my personal "swap to Neocate" trigger, but I know plenty of people do more restricted diets.
It probably makes sense to cut out all four temporarily, but do then reintroduce each seperately to confirm that they are causing a reaction, just like you have done inadvertently with the dairy. You don't want to be unnecessarily restricting your diets longterm if you don't need to.
I don't know about the spelt but I'm sure someone who is GF will be able to help soon. Jen x
Jenny, just spoke with a friend with celiac disease. She says spelt flower is low gluten but not gluten free.
she says she uses rice flour mostly x