I have had this my entire life also. Weight loss greatly magnifies this effect for me. I have tried every known sleep inducing agent that has a short half life, yet they always leave me with the "hangover" or they simply stop working altogother.
My solution? Low dose lithium, we're talking 75mg, 150mg, maybe a max of 300mg (as opposed to the 900mg-1200mg range which is for bipolar). It can even be used every other day. It doesn't work instantly, I allow about 2 weeks for the effects to become noticable.
At these doses it will not sedate you, but it will keep you asleep without feeling drugged. Also, the effects at this dosage are drastically different than those attained at high doses (lack of weight gain, etc).
And I don't have bipolar, nor does it run in my family, I just happen to have a history of long enduring insomnia.