You are a friend... not a social worker nor Psychologist.
It is draining you. That is okay.
And her problems are ongoing and chronic.
And there is no end to it.
It is a hard situation for her.
So, tell her.
Before you get psychologically & emotionally.... burnt out.
Professionals, are able to "detach" from their clients problems.
But you are a friend. You are too close to be impartial and detached.
THUS, recommend to her, to find a Counselor so she can vent to that person.
As a friend, I am sure she does not want you to get... damaged yourself.
Being a good friend, ALSO means, knowing that, it is dragging down the other person. AND respecting that.
No friend, should be used as a dumpster.
Your friend needs to find a PROFESSIONAL to talk to.
I have gone through this too... BUT with relatives.
I had to... draw an end to it.
Because, it is just TOOOOOOOO mentally and emotionally, draining for me... and then, I get very unhappy.
And it drags you down and then affects your daily life, too.
NOT good.
You TELL your friend, you cannot do this anymore.