Actually, I'm experiencing a similar problem. I happen to be on Lamictal, and have been on it for a while, but the balance problem I noticed became an issue when I went up to a higher dose of Seroquel. Come to think of it though, my Lamictal was increased only a few weeks before I started experiencing the dizziness.

The key for me is not to take my meds too late, or I stumble the next day, get dizzy, and almost feel that I'm going to pass out if I stand up too soon. Sometimes it's very hard to get up. I even had a blood pressure reading on the low side on one of those days.

So....I wonder if it's Lamictal in combination with Seroquel and/or Klonopin? It's definitely something to address with the pdoc.