How do I get my friend back?

my friend Anna is really mad at me right now.
She said im not spending enough time with her and that im laways with other people and that she doesnt know if she wants to be friends anymire.
we’re best friends, though … I don’t want to lose her she’s really important to me but she’s really mad, i tried talkiing to her but she reaolly didnt say much other than that she was mad and that she didn’t want to talk to me.
How do I Get her back?