I felt like this on Topamax. I'm still on it, but I decreased the dose and felt significantly better. Abilify and Geodon are also helpful for anger and rage issues (in the same class as zyprexa) and tend to be a little more stimulating and less "mind numbing". Brintellix is also a new serotonergic antidepressant that's supposed to be really helpful with cognition, memory, word recall etc. I'm currently on this now and while it hasn't been a miracle drug as far as the depression is concerned, I have noticed positive effects cognitively. Maybe some things to discuss with your psychiatrist.
Just a personal note, it would bother me if my psychiatrist wasn't willing to work with me to find the best combo of meds to help me be my "best self". Maybe you need to find a new psychiatrist?