I understand where you are coming from. Your Dr. doesn't want you to being the doctor but that is his/her problem.
Remember you are in control and if one drug works better than another and they are the same type of medicine then it shouldn't be a problem.
I take 90mg of cymbalta for depression and 3mg of zanax for anxiety and 10 mg of ambien at night. You need to tell your Phys doc meds are not working and need adjustment because your anxiety is causing panic attacks. Also if you have a primary doctor who knows you well he/she can make that adjustment and write you the scripts that you need. But I wouldn't tell your doctor you took a friends meds this will cause a big red flag.
Best wishes,