Girl's Behavior

I thought this girl liked me but then I was wrong and now it turns out she lied?

(This was a while ago, I never posted this question but I'm still curious). Anyway this girl who I've caught notice of inside my school. About a week ago, she would always pass by my math class, and sometimes we would do eye contact. That same week I caught her in the hallway and I told her I liked her hair and she said "Thank you" before going downstairs and passing by my math class again (We made more eye contact), the way she took is also a detour to get back to her class that passes by my math class. Afterwards I caught her in the hallway that very same day (She was in front of me, about 10 feet) and she looked back when she was with her friend. This week, I told her she's gorgeous on Twitter and she retweeted what I said and then tweeted "Omge" with some emoji's before removing it completely. About a day or two later I saw her again in the hallway (She was walking behind me) and a few blocks later I caught her again in the hallway and she looked directly at me and we made eye contact again. Finally when I got home, I tweeted "I should've said something to her. . ." and she favorited what I said before quickly unfavoriting it. I know for a fact she's looked at my Twitter and she looks at me a lot without saying anything but we make eye contact, whenever we see eachother in the hallway she normally looks at me. Anway I finally confronted her and I told her how I feel about her and asked her does she feel the same way about me and she told me she has a boyfriend and i thought that was it until she tweeted "Another year w/o a valentine" so she lied to me, bf has another valentine, or never liked me.
I thought this girl liked me but then I was wrong and now it turns out she lied?
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