What Causes Loss Of Body Balance Along With Heaviness In Head?

I will be perfectly fine and the next day not be able to balance myself when I am trying to walk. It comes on suddenly. I can be fine for a week or so then wake up and can not walk straight. My head feels heavy. I am in bed all day. I had a brain cat scan and all was well. I do not not know if it matters but I have a bad back. SORRY to bother you of course you want money. What else is new