I hate to say it,but i am just gonna be blunt and honest as usual(i would hate it if people would try to sugarcoat the truth for me)...anyways,she's just not that into you anymore. Either because there is someone else,or she just got bored with the relationship you guys have,and maybe wants more out of the relationship or just wants something different. Either way,why speculate?? Save yourself the time and the headache of trying to figure her out when she clearly turned a deaf ear to u,and either give her an ultimatum (her telling u what's wrong,and maybe you guys can try and salvage that relationship),or just end the relationship.Either way,why prolong the emotional suffering?!