Depression is very common in benzo tapering (from what I have read especially so with Valium) but everyone says this will get better.
I suffered INTENSE anxiety and terror earlier in my taper and now I deal more with depression. It comes and goes at random hours of the day - no obvious reason usually...
I have found the best way to deal with it is distraction - exercise (if you can), call someone you care about, pamper yourself, eat as well as you can, best of all for me laughter! Easy TV that you can lose yourself in and "escape reality" for a while and shows that make you laugh - amazing what that can do to help lift your mood.
This WILL go away - it might be something you just have to accept for now - acceptance is a big part of this thing.
Hang in there,