I can so relate to this, as a single mom of three. When I'm super stressed, I find focusing ONLY on doing the next thing in front of me helps me regain perspective. When you can forget about all the other stuff that's blowing up around you, you are better able to accomplish the one thing you're doing, and this gives you a slight sense of power. Then, you go on to the next thing, and your sense of control increases again.
Writing lists also helps me; but lists don't help everyone. It depends on your personality type.
I find it's easier to put the worries and stresses on hold when I intentionally give control of my life to God, in prayer. That way, I know he's got my back.
Blessings and peace to you. You and your daughter are not alone.
Oh yes - take the B complex vitamin, for sure!