All those things you feel are normal after breaking up with someone you really care about. You feel lost, fear, upset, anxious, lonely, worthless. You want to call her and contact her most of the time. You keep visiting the past, analyse it, and hope you can change it. You just can't even accpet the breakup and can't imagine life without her. You even want to cry out and wonder how can you survive.
It's the way I used to feel and I think it's the way most people feel when facing with this situation. I can't tell you when it will go away, when will you totally heal, and be happy again. It takes time and it varies from one to another. It may take months or even a year, I just can't tell you.
What I can tell you is ACCEPT THAT IT'S OVER. It's normal to think about her, to still feel so painful, to still wants to break NC, and feel so upset. But please stay focus on the fact that she no longer wants to be in the relationship with you and how can you be happy if you have to be with someone who doesn't want to be with you? Sometimes feelings change and there's nothing we can do to change or force someone to be the same person we want them to be.
GO NC for your own healing, of course you will still feel the pain and will still think about it, but STAY STRONG, DON'T GIVE UP, TRY TO FOCUS ON YOUR LIFE, AND DO WHATEVER ACTIVITIES THAT MAKE YOU FEEL HAPPY (ANYTHING THAT'S NOT RELATED TO HER ). When you think about her, try to divert your minds and do something else. It won't go away in a month or two, but always stay positive and focus on you. It will get better and better and it will fade away when time goes by.