Welcome to Just answer !
I am sorry to learn about your problem and i empathize with you.
Well you see it is your unconventional work timings which compel you to remain awake at odd hours of a day which has disturbed your circadian sleep rhythm and insomnia is a repercussion of this disturbed sleep-wake cycle. The condition that you are suffering from is clinically termed as Shift - work sleep disorder ( SWD) and it is seen in those people having work timings which are not conventional ( 9 am- 6 pm) .
I am sending you a link below which you can go through to learn more about the condition and to become aware of some daily routines which a person with your condition should adhere to in order to get a satisfactory sleep during the day despite of the odd work hours.
Now other than this , since it seems like you have developed resistance / increased tolerance against ambien (zolpidem) which explains why you are not getting sleep after it's use like before , so i reckon you should try another sleep aid drug like --
1) Lunesta ( eszopiclone ) at dose of 2 mg before bedtime , if not getting enogh sleep on this dose , the dose shall be raised to 3 mg before bedtime.
2) Trazodone at dose of 50 mg before bedtime ( 1/2 - 1 hr before sleep) , it is an anti depressant drug but being used frequently and successfully for insomnia as well.
3) Valdoxan ( agomelatine ) at dose of 25 mg, 1/2 - 1 hr prior to bedtime, it is an anti depressant drug which is unique in resurrecting the disrupted sleep circadian rhythm / sleep -- wake cycle .
So all of these 3 very good options are there for you to try , and each of them unlike benzodiazepines are less susceptible to abuse and dependence and thus are much safer in comparison to a benzodiazepine.
Kindly discuss these with your prescribing doctor and get started on any one of them.
I hope this helps.
Wish you all the best.
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