What do I do now?

Well I guess I am struggling with the fact of not having someone there for me like I have had the last 5 years. It is really hard when you let someone in on your life like that and then you have to just let that person go. They know they hold all of your little secrets and have all the power in the world to destroy you. I think I am being destroyed but I don't know. I feel like it, she has been on my mind every day and I can't help but think that I let her slip away. I think my life can be summed up at this point by the song from Keith Anderson, "I Still Miss You". I think this is just a phase but it seems like no matter how much she tells me and hurts me something keeps taking me back to her. I don't know what it is but something is telling me she is the one. But the problem is I don't think she feels the same way. I have been trying to move on, its hard after you spend a quarter of your life thus far with someone. Its hard to fill that exact void that that person left inside of you. As I see it now, I dont think anyone could fill that void. But I guess I will just have to press on and wait? Or do I press on and look forward? Its just hard, I think I am having my mid life crisis at 21..haha I have to work my but off to get into the apartment I want, but that is not coming easy, hard to stay as busy as I need to be. I have everything I need to do for graduation from WMU, if I get all my classes taken, I have medical school stuff I need to be focused on like the MCAT, registration for fall classes at Western and Valley, studying for my MCAT class that I am taking. There is just an overwhelming amount of work to be done.. Not that I can't handle it its just hard to come home to mom and dads and not have that someone there to talk with to ask me about my day, or to eat dinner with and then go to bed with at night. Kinda depressing, I am used to doing alot of things that I want/need to do on my own but after you have let someone in who helps take some of the burden off of you and then it all shifts back to you it becomes a struggle, like getting caught under the pool cover when you need air. I just have it kind of rough right now, and I don't have really any friends who care or a best friend now to sit and talk with about what is going on. I have lost the bestfriend. The only thing that is really keeping me going is the saying: "When you are down to nothing, God is up to something..."