Awww Elysium,

You could never know what was going to happen. Some people can share places with others and it turns out great.
But it hasn't and you really do need your own space.

I shared with two different people for months. I have lost them both as friends. The second one kicked me out (we were friends) but she couldn't share space. The thought of sharing space now just makes me feel creepy. Sometimes in life we learn things about ourselves the hard way.

Maybe you could offer to help find your friend to another flatmate like Maven said.

Don't take the guilt trip hun. If she is doing this now, imagine what she would be like if you stayed with her over other little things that may crop up??

You are only responsible for your life. She is responsible for this long standing mess she has gotten herself into.

Take care hun