What should you do when you find the perfect woman you can not have?

Hi, I want to apologise in advance for any grammatical or syntactical mistakes I make. English is not my first language. I am a guy in my late twenties and I have had a major emotional crisis over the past couple of months. It was the first time in my life that I felt this way and I have nobody to turn to with my problems. At this point I just wish to tell my story to somebody. I apologise for the length but what I have is perhaps not a simple situation. For most of my life I have been a loner, but I have not been lonely. I don't have any friends at all, and I am not exaggerating with this statement. I don't go out. I don't go to parties. The only things I leave my home for is work, shopping or sports (jogging, bycicling, etc). But this is all by choice. I chose this life and I was fine with it. It is not as if I am an anti-social person, not at all. I am very good with people. At work or on other occasions I have long conversations. I tell jokes; make people laugh. Most of the time people seem eager and interested in what I have to say. It's just that I don't care much about them. I wouldn't know how to be somebodies friend even if I tried. Three years ago things changed though. I worked at my local university as a teaching assistant while working on my master degree. I taught introductory courses in computer science. My professor and I got along very well and I was the most senior person (after the prof of course) working at our chair. Then we got a new colleague. A very special young lady. As the most experienced staff member it became my job to show her the ropes, work her in, etc. We had lots of opportunities to talk and to get to know each other better. I do get along very well with all my co-workers but with this woman things were different. This may sound cliché but I can say with all my conviction that she is the most remarkable and inspiring human being I have ever met in person. She is well educated (working as a TA after all), smart, cultured, well spoken, humorous, naturally curious, patient and friendly. It also helps that she is young, physicall beautiful and very athletic. It is almost cruel how perfect she seems to be and how insignificant she makes you look in comparison. If she was a character in a book, you would roll your eyes and groan because of the ineptitude of the author. But seeing such a person in real life leaves you awestruck. You might think that I have a crush on her, but more than anything else I admire her. I see in her what I could have been if I was a different person. If I was trying harder. If I was more motivated. Perhaps if I had a better upbringing. What really made me realize all of this though was not so much her behaviour, but mine. I noticed that I changed my ways when she was around. I smiled more; my mood good better immediately when I saw her. On the days I anticipated to see her at work I was happy to get out of bed in the morning because it would give me an opportunity to meet up and talk. Time passed by though and I finished my masters degree. I had no reason to keep working there; in fact, I had already a job in the private sector lined up. That was the moment it hit me: this was it. I would not work with her anymore and there was no reason to ever see her again. This feeling was something I never experienced in my entire life. For the first time ever I was genuinely sad to say good bye. It made me realize what missing somebody truly means. I feel this way now most of the days of my life and it is difficult to shake it off. I have always been alone, but now I am lonely too. I wanted her as a friend, but I don't know how to make that happen. I don't know how to become somebodies friend or what friends do. After work, on my way home, I sometimes find myself daydreaming about her. Imagining what I would say to her and what stories she might be telling me. In my mind I go over the first day we met, over and over again, and I imagine different scenarios how things might have gone if I said something different. In my darkest moments I have fantasies of how I might have impressed her. If I would be more physically appealing. If I was rich or very talented in some way. In my mind I keep believing that if there was something interesting about me I would not have needed to try and be her friend. That SHE would want to follow me around for one reason or another. It is foolish of course to think that way. What I really need is not to be exceptional but to be normal. A year has gone by now since last I worked with her. There has hardly been a day when I was not thinking about going up to her and telling her how I feel. But how could I? I don't even know if she has any interest in me at all. She has plenty of friends. She is a young, smart and attractive woman. All the doors in the world are open to her. I on the other hand feel as if I have been born an old man. They say you are as old as you feel and I feel more than twice my age. I feel like I would just be bothering her with my sob story. As if I would almost force her to take pity on me. To fix my problems instead of dealing with her own life. How could I ask that of anybody just like that? Because she smiled so much when we were together? Because I made her laugh in conversations? For me these were special moments, but to her it probably wasn't anything unusual. For all I know she had similar experiences with all of our co-workers. Maybe I didn't even stand out. There is more to the story of course. There always is. But I can't write about it right now. I don't know how many people will read this, or if anyone will care. Just know that it does mean something to me if you leave a comment. I don't even know what I want to hear from you. I guess there really isn't much you can do to help me. But I really needed to tell my story to somebody and I have no one to go to. Thank you all.