How do i find out about my son?

my son was home on his r&r from afgh. for 3 weeks ,, i took him to the airport on tuesday the 14th , i talked to him once before he left the states ,, but haven't heard from him since , he told me he would call me when he got to kuwait ,, is there a way for me to find out where he is ?? i haven't left this house alone because of not wanting to miss his call , i've been sick on my stomach from this , i need someone to help me find a way to find where he is ,,he;s in the army , he's been in for 4 years, i hadn't seen him in a year when he come home this time