I am 6 mths clean from Herion and Meth and I still cant sleep without some aid.I dont know what the answer is but after awhile (after the craziness of sleep deprivation) your body just gets used to it and soldiers on.I feel for you as it is the worst thing to struggle with.I wouldnt wish Insomnia on anyone.It sucks big time!!!
Keep Strong and try to cope without the medication as this will cause larger problems for you.
Good Luck!!!!