What part or parts of the brain might cause difficulties in equilibrium & language fluency in a 47-y-o female?

I'm on several medications now, including Lithium, Klonopin, Lamictal, & Zoloft. I take all in very low doses, and all but the Lithium for several years (started that a few months ago). I plan on getting a referral to a neurologist ASAP, but like to be informed & fully participate in my health care. My problems lately have been disturbing. First, I am very clumsy and stumble quite a bit. I also drop, spill & knock things over a lot. My brain doesn't seem to know where my limbs, hands & feet are. Second, and most comcerning, is that speaking, writing & typing correctly has become a frustrating chore. Often, I can't spell simple words, have to ask my kids Longer words are REALLY a problem. I reverse letters a lot, retype words w/out realizing it. I've begun to stutter a little at times, and often don't know what to call things I'm trying to talk about, even my kids' names. But reading is no problem. My memory sucks. I'm intelligent, have always been good at these things, so this is scary