I'd be suspicious of those temperatures if they're the same. Under arm should be 1 degree less than oral.

Lots of things can make your body temperature low. Dieting is one. In fact, low body temperature is a positive marker for life expectency amongst people following calorie restricted diets.

I know a lot of my symptoms went away once I got off the things I was eating that were food intolerances.

It wouldn't hurt to get your thyroid checked though, next time you get a blood test done.