I feel your pain. I moved into a new condo when my cats were 9 years old. It was traumatic for them to have a new home -- and there was still construction going on in the building. The condo above me was being finished and VERY noisy. They hid out a lot. It will probably take a week or two after construction stops for Bradley to get his balance back. It is a VERY good sign he is eating and using his litter box. The best sign. Once the dust settles, you'll have your kitty back to normal.
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Tammy and Pookey
(Stanley 8/91 - 8/07)