Mixed Signals? Girls help!?

So my ex gf and her bf (who was formerly my best friend and roomate) broke up a few months ago. me and her were still friends before they broke up and we talked a bit on the phone, but not all the time. Since they broke up we've been hanging out everyday, she's calling me all the time and I've slept at her house a few times (we've didnt hook up). We flirt and we cuddle and stuff, but I don't know if shes doing this just because shes comfortable with me and trying to get over her bf, or if she actually wants to hook up with me again. They were together for a year, and shes bitches to me about him a lot...I'm just really confused, is she just using me to get over him? should i make a move on her?