How could I know what does she feel?

Is it possible to understand what someone feels just by sensing it?
There's this girl. We looked at each other constantly last year, then she added me in Facebook. I wrote to her the next year, we got on, but I have a feud with her friends. That was a problem. She kept on looking at me very persistently, but most of the times she turned her eyes away when I caught her look. We met officially on a party where I told her some rough things. I wrote to her after that and we made up. Afterwards she was the one to say Hi first. Then I felt as if she had lost total interest or moreover - she just doesn't care. I was falling for a boy then and I dived into it, leaving her on backstage. For a couple of months - nothing. Then it got back. I caught her from time to time to look at me again. She never looks at my friends, when we walk by, it is always me. Otherwise - no interest at all. I smiled at her once, she turned her head ignoring me. After that I wrote to her once - fail. Then she said some good things about me on my 2fake birthdays(a joke in Facebook) and commented my profile picture with a playful tease. One day I smiled at her again, talking on the phone and she returned it. we were alone in the hall then. the same day she said Hi (we dont say hi). time after that I wrote to her again, it started out normal, but there was no time. after a week I wrote to her about something but we didnt talk about anything else and she didnt answer to my last message. it seems to me as lack of interest. that's shortly the story.
I'm asking for an opinion how does it sound. And Is there any way I can find out what is in her head without telling her too much. if there are ideas.

You can sense what another person is feeling from their body language. If you get into the personal space of someone who likes you, they will snuggle closer. A person that doesn't will back off. When you touch someone watch whether they move toward you or away.

What you write sounds like she is either very moody or she's playing mind games. Either way it sounds like any kind of relationship with her would be a struggle to keep on an even keel.

i think she's ignoring u and she don't give u any attention so she feeling like "hey I don't caire about her " . u can find out what's in her head from her actions and what she do u can understend that she's playing around with u as u said u smail at her but she turn her eyes and u think that what friends do me I don't think so , :'( ,,,,,,,,,,,,, the point is no interesting on u but if u like her so mutch u can ask her but no derectaly make it like u will say why u acting like this and why u turn when I smail to u ............ u know what I mean ,good luck ,,,,,