I have diabetes. What you are experiencing is called hypoglycemic unawareness. I can hit the mid to low 30s before I'm truly aware I'm crashing. I have my own suspicions as to why, I'm starting a continous glucose monitor tomorrow.

Sometimes I can have brain fog, I may or may not be going down, a few finger sticks will confirm that.

Why not keep a log of finger sticks, take into doc? The meter and strips from Walmart are inexpensive, and accurate. I suggest an am fasting stick, then 1 and 2 hours after each meal. Keep track of what you eat and drink too. Might help you and doc pinpoint a problem, if indeed there is one