Why tf is she ignoring me?

There this chick at work we used to be on good terms she was very nice and friendly towards me but recently she started acting like I dont exist she will approach other guys in front of me, through the day she will talk with everyone in the place except me, when I used to be the person that she will talked the most to before :( man it hurts i really liked this girl very much and thought we had something serious going on but I've lose all hope the last time we speak nothing happened everything went good why she changed her behavior she was so into me and keen to talk to me every day rn what happened?
Why tf is she ignoring me?
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