Danger, Will Robinson!

The other day, I headed out to get in my car and drive to an appointment.  I pushed the usual button on the elevator, rode down, and when the door opened, I had no idea at all where I was, or why I was on that particular floor.  I froze, not knowing.  I backed up into the elevator, looked at the buttons uncomprehendingly.  My building is a bit confusing in that the front door is on the second floor; the ground floor is #1 and leads to the garage and laundry room and a street exit. But I've lived here for 21/2 years. It should be fairly second nature to me.
I panicked a bit. Just a little, in a sort of wtf way. Shook my head and decided to try going down the hallway - and once I had walked about ten steps, it became clear where I was.
It's one of the few times I've had that experience. The other brain things that happen are forgetting the names of people I've known for years, losing any concept of numbers, gradually losing everything around my apartment.
Right now my place is a mess, with way too much stuff piled around in messy heaps because I am trying to clear everything out I do not need and reduce my moving costs.
I feel as if my brain is floating rather unattached. Perhaps it's just this that has me confused. I hope so!
Danger! Danger!