HM -
This seems to be a recurrent theme among us all here, recently. For myself, instead of thinking about dating, I have decided that I want to build up my base of friends (a la Sex and the City). Like you, too many of my eggs were stacked in xH's basket. And I do feel like I am more like an early-20s, rather than a practically 40. Life, take 2.
The days of loneliness do start to spread out, though. I think I have a year more into this that you...they hit, but not as often. There were times when I couldn't get out of bed, even if the kids were home. Not anymore - now, I know what the triggers can be, and the plans I make seem to keep me above it (for now).

An idea about your daughter - you work in a school, with a social worker and school psych, yes? Can one of them offer some help for her? Or someone from her own school? They are usually understanding of these situations and want to help....

I'll write more later...