I remember that wobbly feeling when I told my AH that I was leaving. I did not give an ultimatum; I simply left when I knew that I had to. I did talk to my DD17 before hand, and gave her the option of being away when I had the discussion with AH. After that, I simply had tunnel vision and did what I had to do. It did no good to think about things too hard after I made my decision...I didn't want to second guess myself.
Use this weekend to prepare for what is likely the inevitable. Copies of important papers, making sure that you have enough cash, clothes and other essentials for at least a week. Might even be a good opportunity to look at rentals? (Don't know how far along you are) Just breathe and take one step at a time.