It's a matter of what works for you. It may take trying different meds. I know it's difficult and we want that quick fix, but I know from experience it can take a while.
After my last hospitalization, my Dr sent me home without anything for my panic. I didn't last that day. I called her and we talked, and she agreed I needed to be on something. She started me out on a low dose and she gradually increased it until we found the right dose. I take regular doses of Xanax - 2mg at night and 0.5mg in the morning - and I can take additional doses if needed. But I make sure I let my Dr know when I'm doing that.
Talk to your Dr. You may need to take a larger dose or try a different med. I know Xanax is addictive, but I need to take care of me now. When/If it comes time to reduce or come off Xanax I will be in a better place and better able to handle it. I also know that my Dr will be there helping me.
Good Luck.