What Causes Rise In The Anxiety Levels Despite Taking Clonazepam?

my husband is taking clonazapam for anxiety. for the last three days his anxiety has gone through the roof. he takes 1/2 a pill of clonazapam and is scared to take any medicines that he takes on a regular basis. he cant be still, he has to be going somewhere at all times. the other night he had to get back on his pain pills. well he got sick and felt like he was gonna throw up. well he did throw up, and he had been habing trouble sleeping and wanted a sleeping pill that his doctor put him on, and then when he was naused i gave him a phenagren then he went to bed. he slept all the next day and then the day after is when his anxiety started acting up. could i gave him to much medicine