How do i find a person i have lost contact with?

My gf just disappeared... her cell broke n we only commnicated thru AIM and she would call me ever night from here house or brothers cell but she would always call from a blocked number and one day she just nvr got on AIM n i havent heard from her since and i know u didnt just breack up with me because none of her friends have heard from her niether. i just need to find her n make sure shes ok.... how can i find her???