What are my rights

We currently don't have a legal custody aggreement of our 2.5 yr old son.  The mother has been in and out of jail for drug use for the last two years.  I have raised my son by myself with help from my family because I work out of town sometimes during the week.  Yesterday I come home from work and there is a note that she went to rehab and took my son with her.  Apparently there is a rehab that take the child along with him.  I am freaking out becasue I don't know exactly where my son is and how she could just take him without my consent.  The rehab is hours away.  I want to see my son but don't know where to begin.  I can't call and find any info due to privacy laws at rehabs.  I should be able to go and see him correct?  I just need some direction becasue I can't deal with my son living in a rehab.  If working out of town is the issue I will quit my job today.  Please help

 

THanks