I m a 74 yr old female & looking for a safe sleep med that s affordable. I ve taken a 5mg. Pill the last 2 nights, but not getting more than a 3-4 hr. Sleep. I ve read that melatonin can be negative in a certain part of the brain. So, what is the Max doseage... I intend to take 2 - 5 mg tabs, tonight, & hope it works. What is your opinion as a Dr. Thank you in advance, Marie g Hilton Pollock Pines, Ca.