Hello, I am in the process of getting over Influenza A and B and started having a lot of anxiety. I started taking Ativan 1 mg to sleep, however, I feel horrible in the morning. My doctor prescribed Xanax this Am for me, and have used in the past with a lot of success, however, when I tried .25 I didn t feel any anxiety relief. Does Xanax have to build up in the body for it to be effective. Thank you!