Listening to negative stories without feeling stress.?!

Listening to negative stories without feeling stress.?

I'm seeing a girl who has a depression.
so she always give nagative stories to me.
but it is not easy for me to listen a nagative storie..

I'm going to add details..

When bad thing happens to her, she always tells me
what is wrong with her.

She says that it hepls her, when she talk things to me.
So I am tring to be with her as much as I can, or at least
keep in tuch with her all the time by Email..

but listening to her negative storis are not easy for me..
some times I really get stressed and I can't stand!!

are there any ways that I can listen to her stories without
feeling stress??

tell her how you feel when she tells you the stories