Why does she no longer talk to me..abit of a story :D?

I've met a few people like this in my life but this is a mystery and I just dont get it. I dont really have any enemys and always try to stay friendly with everyone. Ok so about 6 months ago I met a girl who I knew at school and hadnt seen since. We clicked instantly and started seeing eachother alllllllllll the time and basically I fell in love with her and vice versa, got butterflys which i never get, and basically actually thought she was the one. so about 6 weeks later I go back home and shes off with me, fair enough cos I'd got a tiny bit emotional when an ex sent me a deep message..a few days later we're on the phone and I say whats up, she says shes giving me space, I say umm i dont want space, she says look lets just chill out cos u have ex issues, I say look I either wanna see you like we are or not at all and in the end we somewhat amicably agree not to see eachother anymore. Soooo that was 6 months ago..now whenever i speak to her (uber rarely)she hardly says anything and today she was like 'i have nothing to say to you' like when i was like whats up. so why oh why is she like this i cant see a reason!!!!!!!!!!!!!!!!!!!!!!! grrr the mentality of women is too deep :(