Don't you wonder why after 5 years together and only one moment of madness she won't give you another chance?
Maybe she felt relieved when the relationship was over. Maybe she wanted out but was too cowardly to end it and you did her a huge favour. The fact she doesn't want anything to do with you after all your efforts suggest she checked out long before this moment of madness of yours. Maybe she realised you weren't compatible after all. If she truly cherished the relationship you had she would forgive you and try again. As she doesn't want to do that you have no choice to but respect that and accept that.
You are really struggling to move on. You should talk to a professional and find out what is stopping you from progressing naturally through the stages of grief.
Some people are drains and some are radiators... Keep clear of the drains and hug the radiators!