When Is It Time?

How does a person know how much time is needed after a break up to feel better? There should be a set time and day where automatically the person feels better and doesnt cry or think about it anymore. I wanna stop feeling like crap, I wanna stop thinking about him, I wanna move on, I wanna be happy, and most importantly I don't want him to walk out of my life forever. After two years with him and now nothing is left. He is literally walking straight out of my life never to be seen or heard from again, after graduation he goes to paris for a month and then goes to North Dakota for school. How can I just let him go after two years of great memories of seeing eachother everyday to never seeing him again. It's not fair and I hate it. I'm sure it will make moving on easier but I still can't believe this is how it all ended. It's been a month and some since we broke up and it still hurts like I know it would but my best friend seems to think I should be done hurting. I can't make her understand that it is big deal and that why I wanna know when is it time to feel better? Who decides when? What makes the decision final?  I just want to feel better already so far 2011 is not my year.