Is It Safe To Take Clonazepam For Anxiety And Panic Disorder?

I was given a script for clonazepam a year and seven months ago. I was diagnosed with PTSD and anxiety/panick disorder just recently, but have been able to maintain this disorder without taking meds. Right now I m having legal problems and just recently lost my mom, so I took one of the clonazepams I had from almost 2 years ago. Would that script still be considered legal.