You sound like you could be dealing with depression. You might need to add on an antidepressant. Or maybe back off on the Xanax a bit and see how you feel. Since Xanax is a central nervous system depressant, maybe it's bringing you down too far. The blah feelings and lack of focus you describe could be depression or side effects of too much Xanax. Just something to consider.

Sorry to hear your blah feelings are getting in the way at work. I can see why you're worried.