I wanted to clarify that yes, I do work 12 hr shifts. I don't know if it makes any difference but I work night shift 12 hrs. This is the reason that I cannot have someone stop by to check on Gizmo. Although I may be able to get someone to stop by at 1am or 2am in an emergency, but there just isn't anybody that will stop by regularly in the middle of the night.
Just a little update: Things seem to be going a little better. I have gotten him multiple different textures of chew toys and interactive ones, & he seems to really like the diversity. Also, he has learned to play ball & I have been spending extra time with him playing ball to use up a little bit of his energy before I have to leave to go to work.
Thanks again for all the help and suggestions.