@ddljohn-- You might want to ask your doctor about this because everyone responds a little bit differently to melatonin supplement withdrawal.
I experienced the same symptoms when I stopped taking my melatonin supplements abruptly. I do take them now but I give myself a break every once in a while. So if i take it during the week, I don't take it on the weekend. This seems to prevent addiction, at least in my case.
Many doctors say that melatonin is natural and if you suffer from chronic insomnia, you're better off taking it. Just make sure that you're on the lowest effective dose. Of course, don't just go by what I say, double check with your doctor.