I may have said something terrible to my female friend.
What was this terrible thing you said to her?
I called her crazy because I was not getting what she meant.
I'm sorry to hear that you two had a misunderstanding. I think you should realize that using these type of terms to refer your friend could be offensive towards them.
She can be crazy sometimes. I was having a bad day. She was not that mad about it.
It's great that your friend did not hold it against you, however you should still apologize to her It's good to take accountability for your wrongdoings.