I don't understand her, what's her deal?

Met a girl, became best friends...spent a lot of time together. We had trust, respect and all that other stuff...lol. 5 months we were friends. Then she met new friends and forgot all about me. What's up with that?!....she won't talk to me or text me. I see her at work and she ignores me. I think she knows she's on some bs, She won't talk to me, but she flirts around with other guys at work...laughing a stupid jokes....it's like she's ready to laugh at whatever....if someone sharpens a pencil or gets up out their seat to stretch...she'll laugh. She lives for attention....I know for a fact....no one cares about her like I do. What the hell?!....why am I so hung up on this?....lol, It's messed up to have made a friend like that and be forgotten......she has issues......lol, she's on some sort of pedestal....lol................share your stories.....Saying "move on" is just stupid!.....that don't work. I rather find a way to resolve this issue with her......I respect her...I won't just walk up to her and call her out on her bs. Plus, I think she walked away one time I tried to talk to her. lol, It's whatever really. Or atleast...someone out there...who's been through this...or something similar...help me out....how do I forget about this?....how do I make her not important?....how do I get my mind right?....I think I do a good job at doing this at work...I don't look at her...or acknowledge her...but I can't tune out her stupid fake laughter.....it's as if she's purposely trying to make me believe she's happy....n stuff.....lol .....................there are other stuff I need to worry about...I need to somehow erase her from my mind.....please please help.