Are you seeing a doctor currently? Has he/she suggested a sleep study?
Cataplexy by definition: An unexpected loss of power in controlling your body, specifically the loss of muscle control, almost exclusive to narcolepsy. This sudden weakness is caused by emotions, such as anger, laughter, elation, saddness, etc. This brings on a temporary paralysis of the muscles controlling posture and body movement. You may experience a sagging jaw, slurred speach, drooping head, buckling of the knees, or weakness and drooping of the arms and hands.
I experience falling to the ground cataplexy and my experience is that it is very sudden and spontaneous, triggered by emotion. My head droops, my eyes close, my arms and legs go limp. This lasts seconds to minutes. You can hear and are fully aware of what is going on around you. There is not, at least in my experience, loss of memory of what is taking place.
It sounds like you need to begin with a neurologist and have a neurological work up, then possibly a sleep study. I experience some clumbsiness, maybe due to narcolepsy, but unbalance on a regular basis may be something else neurologically speaking.