Just an observation:

After reading the email from your friend, I don't think you're giving her enough credit. It appears she does understand. Maybe not everything, but enough to understand that you need someone there for you right now. Don't shut her out just because you think she'll make assumptions. It seems to me she is very supportive and not really judgemental. I hope you give her a chance to be there for you. You've very lucky to have someone like that in your life. I'm sure you've been there for her too. I hope you think about it.