I Want to Know What Your Worst Mistake In Life Has Been So Far

Turning my back my first genuine friend, I avoided her for a while. At first I didn't know why I was ignoring her, I jut did, and then I really dug deep and realised that I was just scared. Scared of letting her inside mind. I'd already told her more than I have ever told anyone else. I have "friends", but they only know a side of me. So I guess the fear of letting someone know all of me has crept up on me, and now it's cost me a genuine friend. I've apologised, but even I know that's not enough. I want to apologise even more, she has been going through a rough time lately, I'm afraid she's going to go down in a rough spiral however I don't want to nag her. I don't know what else to do. I've never had to deal with losing a true friend before.