I suffer this very very often, but I have hypoglycemia (exact opposite to Diabetes) which is exhacerbated by pregnancy, and am Iron deficient anemic. Both can contribute to this feeling.

I recommend bringing it up with your main health care provider. They can do a GTT, a HGB count and check your BP to see if they can pinpoint what the cause is.

In the interim, never skip meals and snack on fruit (for the natural sugars). Should help keep the wobbles at bay.

I will warn you though that if it is from low blood sugar, the GTT can be even more taxing than just what you are experiencing. I had a hypo in the hospital hallway. So don't wander too far from assistance.