My Buddy has similar issues, I have him on this :
Amazon.com : Cholodin Canine 180 Chewable Tablets : Cholodin For Dogs : Pet Supplies
it has helped alot, another thing I give him when the anxiety hits harder
at nite is this : Anxitane
couldnt get a link from Amazon as its out of stock, but do a search for
canine cognitive dysfunction and you will find lots of supplements and
reviews.
its kind of like sundown syndrome with alzheimers patients
Good Luck !