I feel really trapped on all my meds myself. I'm in a hurry right now but I'll say in brief that I would not make any radical changes to your meds. Be kind to yourself and know that this too shall pass in time. If you need another antidepressant if you are feeling so down, maybe that would be a good thing. I tried to get off mine but got too depressed. I would hold on your taper until you feel better. One thing at a time... maybe deal with the depression first.
Going from 12 to 10 on the valium is too much of a jump. I inch my way down with a scale, but I'm nearing the end, but go really, really slow. Maybe go back up if you are in a crisis... then go slow. All the best to you!