I've also used klonopin to relieve my anxiety and it works unbelievably well and quickly (within ~1hr of dosage). There is potential for tolerance and addiction, but it's worth it if you use it responsibly. I've done a lot of reading on which drugs are most effective for anxiety and klonopin, xanax, and other benzodiazepines seem to be the gold standard. I've come across very few accounts of people who these type of drugs haven't worked for.
One other thing about klonopin and similar benzo drugs is that I noticed since they reduce my physical pain as well (as they are central nervous system depressants) I will overwork my body easily while the drug is in my system so just take it very easy and don't exert yourself while you're on it.