I accidentally unfriend my very close friend on Facebook. What should I do?

Is there any way to be friend with her again without sending a friend request?
Facebook is so dumb. if you accidentally clicked the unfriend button. there should be like confirmation like this "are you really want to delete this person from your friends list. Yes or No?
I sent her a message saying "I'm so sorry, I clicked the unfriend button by accident. Kindly please accept my friend request