Woke up in the middle of the night 2 nights ago, took 9mg of melatonin to help with sleep (shift work) Woke up in the middle of the night with the cold sweats, had a temperature of 37.7 degrees celcuis. The next day I noticed that I had hives . I did not relate this to the melatonin, so i continued taking it for 2 more night, I still have the hives. Is it safe to say that I am having a allergic reaction to the melatonin?