My son was the same. Kept it all in. I worried, too. A lot. He didnt like to talk about his dad or the sitch. Refused to go talk to someone.
I let him know I was there to talk whenever he wanted. Everyone deals in their own way. I think as long as she knows you are there, it's really all you could do right now. I know you are keeping a close eye on her.
It's a tough, tough age to go through all of this. Not that it isnt at any age.
It is so hard to see our children suffer...especially as a result of actions from their other parent. It just isnt how it is supposed to be.
She will be ok, M. She has you for her mother and you are pretty amazing.