Brain fog can be a sign of many things.

OH is diagnosed when a significant drop occurs after standing. So you have to compare a sitting BP with a standing BP.

Your BP's listed look fine, but are these from the doctors office...when you are sitting? Are you taking your BP at home? If not, consider getting an inexpensive BP monitor from the pharmacy and take your BP at home when you are symptomatic. This means if you have symptoms when you stand, then take it when you stand. It defeats the purpose to have a problem when you stand and then sit down to take your BP. You have to take levels in both positions. See if it has dropped from the level when sitting.

A tilt table is one test done to confirm OH...which measures your BP and heart rate from a laying position to a gradual rise to a standing position. There is also a 24 hour ambulatory BP. A doctor can get an idea if you have OH by simply measuring BP when laying on the examining table, then sitting, then standing. Of course, OH is not something that occurs every time you stand, so it's important to check yourself (sitting & standing) when you are symptomatic...then make a log of ALL the measurements in different positions and the amount of drop. Anything over 20 point systolic drop is a indication of possible OH.

If your brain fog is only occurring during these episodes, then it may be related. But you have to establish if OH is a problem first.