My girlfriend(That I very much love) wants me to leave her alone

Hi everyone my name is Glenn and I have been an emotional train wreck the last week or so. I am 24 years old and my girlfriend(or ex..I am confused) is 22 years old. We have been together for almost 5 years and just last week she told me that she wants to be left alone and needs some space to breathe. Now bear in mind I have always been a bit jealous because she is the most gorgeous girl in the world. I would always want to talk to her because I can never stop thinking about her and she is a very busy girl... She works full time and goes to school full time and she's also in the Air Force National guard. From the first day we held each other I knew she was the one for me.... I would have dreams of getting married with her. I actually asked her one day if she ever saw herself marrying me in the near future and she said that she is not thinking about that right now because she is so busy with school, work and the Airforce. She has always said that she loves me and she never wants to be without me and one day she took it a step further when we were being passionate and said "I never want you to leave me". Their parents are very cool with me and they even let me sleep in her bed one night because I had to much to drink on her fathers birthday! I love this girl with all my heart.... And just last week she told me that she wants me to leave her alone because I am always all over her. I admit that I am because we barely see each other much because we are both very busy with work and school and I always like to know how she's doing. I admit I've made my share of mistakes in the past but I think that's what makes us human... She also sometimes gets angry with me and yells things I know she does not mean.. Like the other night I called her around 1 30 in the morning and she yelled at me over the phone for waking her up and accidentally woke up her parents(I was so mad at myself that I couldn't sleep that night). She has told me that if I keep trying to come at her that is only going to push her away even more and that I need to leave her alone.... I know from past experiences that when she's mad at me she will tell me to give her space and I would give her space. But this time is different I have been trying to talk to her about what's wrong and trying to come up with a solution on how we can fix this, she doesn't even answer any of my texts or phone calls so we could talk. I have always given her flowers and I've given her cards that have been handwritten by me with poems of love... I can't even count how many I've written in the last 4-5 years we've been together. She told me the other day that she doesn't feel the same way anymore about(which really hurt!) and that I need to give her space to breathe. I sent her a text that said "I love you with all my heart and I will do whatever you ask of me... I cannot see myself without you and I will do whatever it takes to better myself as a person, whenever you need to talk to someone I am always there for you". A couple of days pass by and nothing... I am really starting to do bad at school because of all this. I hate not being able to hold her or talk to her at night and tell her sweet dreams. I cannot see myself with anyone else but her. We have always said that wet would be together forever but I am really starting to have bad thoughts entering my mind. I really worry about her all the time and I always tell her to be careful when she's driving or if she's going out to hang out with her best friend(which is a girl). I never thought it would come to this I have done everything I can to show her how much I love her and I even said I was sorry for not giving her the space she needed... I even told her I was a complete idiot. I haven't heard from her in two whole days and she used to always text me when she was on her way to school and call me at least twice a day. I am in a state of shock at this present time and its so hard for me because I am so confused about the whole situation. I have a paper and finals this week for my economics and Financial Accounting classes and I have no desire in doing that right now but I have to push myself if I want to become president one day(majoring in Political Science). She means the world to me and I miss her very much and she knows this... But I have decided I will not call her or text her anymore... I need to appear strong to her and not act like such a wimp because I know girls do not find that attractive. I promised her I will change and that I will be here whenever she wants to talk... What do you guys think I should do? I am at a dead end.