Search Results: getting a crush to notice you

To be clear, she is a friend that’s a girl, and I care about her but am unsure about what happened

This might be weird but here we go. She’s this outgoing girl but keeps her feelings & emotions to herself. I’ve noticed that she might have a crush on this one guy in our class who sits with us, she sneaks looks at him a lot & seems pretty shy around him & can barely look at him when they talk, which is odd for her. She only sees him in our one class so I've been able to notice these things. Towards the end of the semester, she found out from someone that he liked her. He & her both knew that she knew. She seemed genuinely happy at first, & she started posting a bunch of selfies on Instagram & Facebook since she found out, which was off because she very seldom posts anything. She started changing her profile pictures a lot more often on days she saw him in class, including the day she found out, etc. But as the semester started ending, I saw that she tried getting his attention sometimes & I guess he never reciprocated, maybe because he was shy also or didn't know if she liked him back, I don't know why he didn't. I said earlier that she always seemed shy around him, I remember one time when she tried talking to him & she clammed up. To make up for it, she tried weird ways of getting his attention, & I remember noticing on the last day of class where they shared a look at each other & she could never look at him before that.

The semester ended a month ago & nothing happened between them at all & she hasn't seen or heard from him since by my knowledge. She started slowing down on posting selfies on Instagram/Facebook, back to normal, but she keeps shuffling her profile pictures with old photos, & a good amount of her new pictures look like she's faking a smile. On Facebook she's been posting a few sad love quotes. She acts fine around me & friends, but seems down when she's alone.

What happened here and is this her having a confidence/self-esteem problem? Why?