Hi Gigi — I follow the paleo autoimmune diet simultaneously with FTD, and both have helped me a lot although each individually allows foods that don’t agree with me. You might want to read about that diet to get ideas of what foods might be causing your problems.
I know how tough it is to find snacks! Pork rinds have no carbs. Nuts are a good snack if you can tolerate them, and cut veggies like broccoli, cauliflower, carrot sticks, etc. (if carrots aren’t too starchy for you) You can also buy/make veggie chips. Beware of the potato chips with a little veggie powder added, but there are just baked/dried veggies. Most are starchy veggies, but I have seen kale chips and seaweed chips. You could also make smoothies with veggies, coconut milk or nut butter, and whatever else you can tolerate. If you can eat eggs, you can make snack bars with just eggs and pureed veggies. Or simple hard-boiled eggs are a good snack. Beef jerky in the store has sugar added, but you could make your own. Canned fish would be an easy snack with no prep, just watch for the added flavors if you decide to try the autoimmune diet.
Keep going, eventually you’ll figure out what works for you!