to be honest im in the same boat as you man, the problem is that shes keeping you hanging:
she gives you IOI's but she never gives you a major sign that she doesnt like you.
instead of telling you straight up that she doesnt want to hang out, she would rather not reply to texts and calls.
Because of this she doesnt deserve a lot of respect.
If a girl rejects you, you get over her
if she likes you, you stop feeling anxious and needy
if she gives you signs she likes you but never replys to texts and calls, she is keeping you hanging because shes too scared of losing your feelings even though she doesnt feel them back.
you can ask her out- if she doesnt reply or says shes busy and doesnt tell you when shes free, imagine her saying "fuck you!" and that will help you get over her.
in your mind she is on a pedestal which is why shes on your mind, you need to remind yourself what her flaws are. eg: shes fucking other guys who put in 1/10th of the effort you do, and shes a bitch for saying stuff like "lets hang out" but never gives you a time.
once you accept this you will feel like a huge burden has been lifted, i know because this happened to me last night.
amazingly, i had the same story as you! what a coincidence!
so i started texting her once we were both back in town and she says "HEY!! i havnt seen you in ages my dear! we need to catch up soon!

"
i replied with "cool, are you free saturday/sunday?"
no reply
2 hours later i give it a last ditch effort and say "ill take that as a maybe then?"
never replied
i went out with her best friend that night because she is attracted to me (lol) we had an awsome time just the 2 of us, and the girl i like went out too but she ended up going home with some dude and probably blew him...
at first i was angry, then sort of sad, then i realised that shes really not worth my effort, or respect and that this will make me stronger, resilient, and not so much of a needy little bitch. So take it as a life lesson, fall in love with yourself before you get a crush on her.