insomnia
"I'm 49, menopausal and I am detoxing methadone (for cancer pain) and every night I find myself wide awake, body and mind despite Rx sleeping pills. I was taking  2- 3mg tabs of melatonin with fairly good results. I have since learned that that is considered a high dose. However I picked up a new bottle and inadvertently got 5mg tabs so for 4 nights I was taking 10mg and it had an opposite effect. I was anxious, my heart was racing, I became quite depressed through the day, and of course I was wide awake. So if you are having any of those problems with melatonin then maybe try a lower dose. I have since learned that a body normally makes .3mg/day so much lower doses make sense. Sweet dreams..."