A bipolar fear of mine

As a bipolar person, one of my biggest fears is that, one day, I won't be able to function EVER AGAIN as a result of my illness. Just that the illness, which we're all still trying to learn and understand, will eventually become total, like Alzheimers, and I'll never be able to work on my book or even be able to take care of the basic things in my life. I'm only 42 right now. Could bipolar overcome me completely in the next year? Month? Week? Will it destroy me today? It's hard to get a prognosis on the illness. It's very scary to me.