My father took upwards of 12mg a day of xanax for his severe panic disorder. That's a ridiculous amount, as I'm sure 2mg would knock me on my ass. But yes, they up the dosage, or switch you to a different 'emergency' medication like ativan..any anxiolytic really. Benzodiazepines are more habit forming, and the withdrawl symptoms are your reason for taking them in the first place...severe anxiety but x 100, so some doctors won't give you much..I'm on sublingual ativan (which if you're not familiar with it, works a lot faster), and usually 1mg is enough to at least relax me a bit, if not slow down the palpitations right away.
I personally am not on any anti-depressants like many are, but may turn to them sooner than later if my own condition doesn't improve. Maybe you can talk to someone about that, if it's an option for you.
Good luck, and welcome to being an active memeber of the forums :D