Losing Love

So hey this girl who I've put my all and poured my heart out to had back in feb had admitted everything about liking me and wanting to be with me, so i start my pre deployment leave and decide to go visit her on the way up to home. I get here, and start enjoying time with her, spending time with her, being the kind caring genuine guy i was raised to be, showing her how much i care, and just showing her i want a genuine relationship. she starts acting differently though after mid afternoon. I was told that she had changed feelings all of a sudden but i aint acted any differently. I went from confidence and knowing that she loved me and that things would work to all of a sudden bam, I feel like once again i poured out my heart for nothing, WTH should i do?