DD knows, even when I worked part-time. For a while I worked the census and could arrange my hours around her school schedule which meant she never had to know when I wasn't home. She still flipped out. There is something that happens where she starts to think "Mom can't come to the school if I need her" and she just loses it.
Funny but she was just asking me yesterday if I was planning on getting a part-time job. How does she do that? I was talking to hubby about the possibility of getting a part-time job while DD was off swimming with a friend. There is no way she could have heard us! Anyway, her friend's mom works all the time which has made for a rather boring summer for her. I wonder if seeing the friend has raised DD's anxiety about me working. When she was asking me about working, it sounded like she was trying to talk herself into believing it would be a good idea.
Still, I hope volunteering - especially at the school - will help fill a hole. Actually, the only part-time job that really worked out was when I did recess duty but DD just thought I was coming to see her at school everyday.
BTW, the unemployment rate in our county just rose to 9.4% - not horrible for MS, but not terrific either.