Where has my SSD space gone?

so i have an ocz vertex 3 60gb ssd. I know it isn't a lot. i wish i would have gotten a 128gb but o well. so all i have installed on my ssd is win 7 home premium, battlefield 3, and just the essential apps like antivirus and google chrome. after i installed windows and bf3 my ssd still had 20gb of free space left... over the past few months.. without installing anything new, if has dwindled down to 7gb free. i run windirstat and it says that my overall ssd size is only 50.2gb. windows 7 takes up 15.4gb and bf3 takes up 17.5gb.. it also says that my pagefile.sys is taking up 4.0gb and my hiberfil.sys is taking up 3.0 im not quit sure what those two things are.

trim should be working and i thought i disabled hibernation..

anyone have any ideas?

~Thanks