What Causes Loss Of Body Balance?

I was working at home when I suddenly felt unable to support my own weight (or at least, it s a lot harder). I got up to get a drink of water and felt extremely uncoordinated, stumbling across the hall. I don t feel tired or sleepy but it s somehow hard to hold myself upright. I keep getting the urge to basically keel over and not do anything. My ears are also ringing a bit.