Start with how much you love her, of course. And then move on to how much you appreciate all she has done and how proud you are of how she is handling things and how proud you are of how much responsibility and maturity that she has shown. I know that as a teenager those sorts of words would have meant a lot to me (and I was by no mean mature or responsible so I did not deserve them).
I am not sure if you have a plan right now to get back onto your feet and reunite the family. But if you do then share that with her.
And then give her permission to be a kid and a teenager. I am sure she is worried about you and I have seen that teenagers seem to feel things with more intensity than older folks. So she may be having a hard time letting go of the worry so she can enjoy herself hanging out with her friends and doing silly stuff. So encourage her to do that because she deserves to have fun. At the same time let her know that you are strong enough to handle the burdens and while you appreciate her support, she does not need to take any of the burden.
((((teeghan & DD))))