Pregnancy causing extreme tooth sensitivity

I've never had teeth problems. I've been to the dentist 11 times in the past 5 months..all while being pregnant.

I needed a root canal, then while they did the build up for that, they filled a cavity above it.

Everything felt fine and then out of no where (probably 3-4 weeks after filling) that same tooth became SO sensitive to cold, hot, food...anything that touched it. It was a lingering pain and didn't go away as quickly as a couple seconds. Well I went back and he re did the filling...which feels fine now.

Tonight. Same thing happened with a tooth on the other side that they filled. Sensitivity to everything. It feels the exact same.

Just called the emergency line. He said it's very unusual for that to happen. But to make sure my toothpaste wasn't whitening. (Which is it...but I've been using it for years) and to go get some synsodyne that has no whitening and gunk it on the area that hurts and see how it feels tomorrow.

Has this craziness happened to anyone else? I never have problems with my teeth and not that I'm pregnant everything is going wrong

A month later I went back to have 3 small cavities filled on the other side.