My 91 year old mother woke up not knowing who or where she is. I gave her her meds but she is sobbing & I feel helpless. Any suggestions?

I worked as a Secretary for a Visiting Nurse org. Our nurses called this an episode. Things can happen overnight and there is no ryhmn or reason. I found with my Mom she was very confused when she first woke up, more than usual. My Dad had heart desease and also had this problem. Its part of the desease. They know something is wrong, they just don't know what, My Mom would cry for no reason and not know why. Your Mom may be entering a new stage, This to will pass as she enters another stage,

That is why this forum was started, I believe.
My husband and I have been thru this twice. Personally, I don't think this is a new disease. Some one , a researcher gave it a name. People are living longer, thanks ? To modern medicine. They use to say back in the day, Senile.

Glad someone could help you right away. We are lucky that we have others to talk to here. Other family members, not so much, I have found. It can be a hard task alone. No one knows that until it's their time to find out. Take care of yourself or you won't be able to help your mom.

That is common in dementia as they sometimes don’t recognize their homes, no less their children....then an hour later they do remember; it’s the changes & decline in the brain

Unless your mom is on Hospice, I would call 911. Or at least call her doctor. A change in mental status is a medical emergency.