This sounds like a problem you need to discuss with your own doctor. You may suffer from anxiety issues of your own that need to be officially diagnosed. Your doctor may then refer you to a therapist who may prescribe an Rx of your own.
Xanax is addictive, and yes, your body relaxes under its influence. (and I know you already know this) but ...your cousin is not doing you any favors & shouldn't be giving you anything. The good news is you have a positive experience with this particular drug, so you can relay that to your doctor.
I wish you luck as you explore your options...