I don't have much to add other than to echo what everyone else has said on here. I am in the same type of boat as you. Gluten-free vegetarian who just had a food intolerance test reveal that I now need to try going yeast-free, oat-free, dairy-free, peanut-free....and the list goes on. I try not to let it get me too down. I go back and forth between allowing myself to have a moment of "this sucks" and then turning around and saying "but in the grand scheme of things this aint that bad". I agree with all the recommendations on here - it's not about eliminating as much as replacing. I can't have peanuts, but I can have almonds! Etc. And the idea of a splurge, or highlight is a good idea too. I try to focus on the things I can have. Like when I find something good that is actually "everything-free" I really celebrate it. I'm hoping that'll I'll be able to reintroduce some foods back into my diet in a couple of months, so I've used that to cope mentally (thinking some things *may* be temporary).
Anyway, you are definitely not alone. Good luck.