Chicki,
I think what you said to your girls is perfectly fine. If your D7 is having a hard time, there is nothing wrong with telling your H that she needs time to adjust and you would like to stay with them. Kids should also be allowed time to grieve under these circumstances. Remind your girls that eventually Dad would like to spend some time with them, but you will be there for them whenever they need you.
It's ok to cry in front of your girls, you're showing them you care about your M and your H. As long as you can be strong for them as well. As parents, we need time to grieve for our loss as well. It's a balancing act to know when to allow that for our selves and when we need to be strong for our kids.

I know the pain you are feeling for your girls, it's the worst pain there is.
UB