I'm allergic to trazadone.
But when I was a child, and not gained an allergy to it yet, it would leave me with massive hang overs, even at four times the lowest dose (lowest dose was split into four pieces).
Along with leaving me with a 24 hour mental fog from when i took my last dose of it, and causing sleep apnea.
But the 3 hours thing, sounds a lot like me last night.. and much in the past... but mine is related to something diffrent.. narcolepsy, with insomnia, plus parents who wont quit waking me up all the time.