I had this as a regular symptom before abx. The Rifampin did make me much dizzier on the first dose. Even for a few months on the full dose, I would have increased dizziness about an hour after the dose.
My upper body and head would actually sway. It is nearly gone now and I am stopping the Rifampin any day now.
Are you taking it at night/evening? Does the dizziness subside before the next dose?
I have wondered if some if my persistant "dizziness/dysequalibrium" is a side effect of Rifampin.
Even Zith lists dizziness as a side.
And yes, withdrawel from Cymbalta could also be causing it. Are you discontinuing the Cymbalta slowly? I realize it is a capsule, but some have opened the capsules and split the doses to wean off even slower.
(I did see your e-mail. I will write when I get my e-mail straightened out.)