What happens if my flatmate moves out?

My flatmate is looking for a house. I should be happy for her, but I’m not. The reason? My current work state is so sporadic and occasional that I just can’t be sure that should she move out, and if I was then forced to move, that would be able to afford a flat or guarantee that I would get it. Every time she mentions it, I get a shiver of fear. What happens then? What would I do?