I'm going to try to avoid my friend
Why do you want to avoid your friend?
Because she feels sorry for herself
If your friend is feeling that way, you should cheer her up, not avoid her. It is expected of friends to help each other.
By talking to her, I am going to make her feel worse, I would feel guilty and lose sleep.
You will not make her feel worse by talking to her. I believe the opposite and that you will make her feel better.