Anyone experienced in taking melatonin to sleep?

I like it because it helps you sleep and to wake up, but it seems if I take too much or take it too many nights in a row, I just want to sleep all day. I wish I could get it right, I keep trying to keep track of what works and what does not work, but if anyone has already done that I would value your expertise much, maybe make it easier to get it right! I have to do something, if I do not I will be awake for months...and the doctor refuses to give me anything to sleep, besides benedryl which makes me groggy, and weak.