Sometimes when I've been really stressed for a while I have a day when I can't get out of bed. As if my body and brain just shut down.
I think that you are having a physical reaction to your new state of mind.
After all those years of stress you know that its almost over and your body is just taking a long overdue rest. I bet you don't sleep properly most of the time due to anxiety so catch up while you can!
Also, when you say you feel bad planning to leave because he is being nice.
Personally I think you should not feel bad - part of your anxiety comes from never knowing when he will be home or what mood he will be in.
Drunk, aggressive, nasty, or nice. They are all just his moods. If you spend your life on eggshells because of his moods and behaviour, then you have to look on him being nice as just another mood that keeps you anxious.
Nothing has come to a standstill, you have made your decision but can't do anything about it at for a few days at least because he is under your feet.
Looking around the house and not bothering about whether you'll miss it or not is a good sign.
(dreadpirate, have you still got that full tank of diesel )