Fed off with a situation

Yesterday, me and my long-time friend have broken up from our relationship, that lasted about 3 weeks, if I'm not mistaken. She said, and I quote "the distance between us is too much" and "wants to keep her options open", and the reason why she did this was because "she didn't want to lead me on". It was online, and she's always mentioned how she hates us being apart, although I suspect the "distance" and "options" mean something/someone else too. 

The relationship proposal itself was very fast-paced (which I quite admired), because of my lack of relationships + my previous experiences, I had doubts. But she encouraged me to try. I've always loved her deep down, and it was the most beautiful way to escape singledom, so why not. She even said the most loving things about me, and even said that she's willing to wait for me and/or I am much more special than people in real life. (This is more of a summary of stuff she told me.) 

That was, until 2 days ago, when she stopped talking to me. I assumed this was due to her exams, but knowing her, this isn't exactly true either. What I find the most heartbreaking is, for her other long-distance relationships in the past, one was a few months, and the other was a year or so (on-and-off). So it must've been something about me this time around, and I also made the mistake of being vulnerable to her (I often hid my emotions from her because I wanted to protect both myself and her), and stuff like this break-up is exactly why I am so resilient. 

And I don't want to handle the torture of "being friends" either. I already did that last year, where she always liked to do it, regardless of her being in a relationship or not. This year, I contacted her because I saw one of her profiles by chance, and even before we entered the relationship she told me "how good of a friend I am". 

 Is it my fault, or not?