In terms of you and your DD, are you able to do different things to take your mind of it for a while? Or maybe have some routines tha you do together to get some structure back and make you both feel a bit safer in your current environment.
Not sure that will help but hopefully others will be along soon with other (better) advice.
Does she have any good friends you might be able to invite round for a while after school or at the weekend? Having someone else around may help her take her mind off things a bit. (sorry probably a rubbish idea my dd is only 3 so not sure about 11 year olds)
I saw your post about your DD being away and you having to tell her DH was in hospital and felt awful for you. Hope he improves soon.
You may think that she is too young for this, but when I was an older teenager my mum was ill. I found trying to carry on as normal very hard . At one point we sat down and cried together. I think it helped us both