Most Helpful Girl
Ah I'm sorry to hear that she's unlikely to respond. Ignoring hurts especially from someone you like (I am speaking from experience.)
I think it would be better for you to write it all out and then delete it. Sometimes right after breakups we panic and go overboard expressing guilt and regret, and find out later we never deserved to feel so badly in the first place. I think you should take a few weeks or so things calm down.
Of course, there's nothing wrong expressing your thoughts. If you really want to, go for it. But don't let her reaction get to you.