I experienced the same anxiety and panic at the end of grad school a few years ago. Up to that point in my life I had always handled stress and anxiety with exercise and work, but these methods simply did not work. Let me echo the advice here that you should visit a doctor and ask about some short-term anti-anxiety and insomnia drugs. I was very anti-medication until I hit a wall that I just could not negotiate and felt paralyzed by worry and fear. Drugs don’t cure the problems, but they can provide space for you to re-group your emotional resources and tackle life again.