Corticosteroids do this all the time, but different people are affected differently. Since they're basically adrenaline, the answer might lie in your adrenals, and there are herbs that might help to bring them back into balance, though hopefully time will do this anyway. Some include ashwagandha, holy basil, and eleuthero. This class of herbs is called adaptogens, some are stimulating, some are calming, but all of them balance the adrenals and are used by most athletes. They are mostly found in Chinese and Indian traditional herbal medicine, but there are adaptogens found all over the world -- for example, American ginseng in the US, rhodiola in South America. As for the Xanax, try not to overuse it or use it for too long -- it can help you relax, but for sleep it can interfere with REM sleep and long-term use can make insomnia chronic and they are hard to stop taking if you take them for a long period of time. They also wear off, and their sleep effect is largely an unwanted side effect, as they are intended to reduce seizures and relax anxious people, not to create sleep. Are you able to meditate or exercise? That might at least help until you body recovers.
Sorry to hear what you are going through. I would definately take the xanax for some relief. At least for the short term. If you are not getting any sleep your anxiety will probably get worse.
I would also suggest making sure you are not having anything stimulating around bedtime like coffee, sugar stuff like that.
Try some chamomile tea, it is very soothing, perhaps lavender oil bath and some breathing and relaxation. There are some great relaxation for sleep on you tube and I know I plug in my headphones and put some on and even if I can't sleep it helps me to relax.