Nocturnal Taz

Taz is not her normal self at night.  For the past couple of weeks she has stopped sleeping at the foot of our bed and she roams around the house most of the night.  She is also barking a good deal in the middle of the night, but when we get up to check on things, there is nothing there.  The other two dogs are fine, no issues at all.   She is due for a check up at the vet so we are going to talk about her nocturnal changes.  I am a little worried.

It has been a busy Monday and a rather long one.  I am not sleeping well because of Taz's activities.
How can a little 7 pound dog cause this much disruption?

My tea awaits and hopefully a good night's sleep.  I hope our friends in the Houston area are ok.
Prayers that the rains stop soon.