How to overcome this ??

When I was 15 ( im not 18) I felt in love with someone i knew since a was 5 or 6 ( dont remember the age i fristly met her). I had always liked that person ( without knowing why). I spent some years witout seeng her, but when I was 13, I went to another school then I met her again, she recognized me. But in the next two years I have been to shy, I felt some attraction toward her but she was so beutifull that I didnt make a move, So, two years later, I noticied that we were no longer friends on facebook ( I guess thats normal since we almost never talk). I actually made me very sad xD So I decided to move on. Its strange I felt like I was just realizing that i was in love with her, so i tried to be her friend xD doing really wierd things blushing a lot like a fool when we were speaking, I guess she even understood. The main problem was that I was afrais of telling her my feelings. So for the two following years, I havent told her ( She told me one day she had a bf when I asked her so i didnt tell, someone told me she broke up but I didnt believe that guy lol m and I saw her again having someone else as bf ) . So this year my last school year in this school I decided to do it. OMG ! I feel so ashamed for everything Ive attempted ( I was really behaving like a kid sometimes), I told her that I wanted to tell her something important on facebook, but In fonr of her I couldnt say a word so I "escaped", It was too hard to do for me, I was even sweating . So she told me to tell it through facebook, On facebook I did but she didnt aswer I saw she read it.
She acted like nothing happened.
Some weeks later I wrote another message and she finnally answered, and told me that she was unstable in love then she prefers now to "focus on religious things " thats a litteral translation from french I hope you understand that.Then she told me (not kindly xD) to never tell that to someone ( I hope she doesnt know this website loool )

The problem is that I feel like I cant fall in love with some one else again, I'm really afraid on experencing this again. So guys I really need your help