dude this mite sound a bit retarded but if you are having trouble sleeping have some nice turkey breasts and a cup of warm milk before bed.

they contain chemicals that make you sleepy.

chilled music

a bath.

exercise the morning before the night you want to sleep

in regards to the smoking i would just stop untill your op, as it just makes things less compicated. im not an anesthetic, but it could be that the chemicals they used to wake you are the ones they use to put you to sleep get lessened/magnified repectively due to the effect of the thc in your brain or possibly blood.

a break never hurt and once you awake and home youll be monged like a mo fo

hope your op goes well

peace

ali