I've worked in a sleep lab for 5 years. The education I received from an Ambien specialist said Ambien is not physically addictive in the classic sense of withdrawls and such. That is why people can take it sporadically or as needed. The worst withdrawl symptoms would include 2-3 days of rebound insomnia, after which things should return to normal. Make sure to establish a solid wake/sleep cycle with exposure to daylight and limited exposure to computers,tablets, phones or any stimulating light 2-3 hours before bed (beware of clocks or other things with blue lights). Make your bedroom a sleep retreat, with no activities but sleep and sex. No TV, or other distracting activities. Make sure there is no light, no noise, phones, alarms..... things that seem innocent, but do disturb your sleep. Does your bed partner sleep soundly? Do they snore or twitch or kick or disturb your sleep in any way? Is there a pet or child that disturbs your sleep? Are there enviromental noises ourside that you can hear? (Traffic, neighbors, animals, trains, etc.) Try a fan or 'white noise' device... something soothing to drown out other noise. Avoid alcohol, caffeine, chocolate, allergy or other stimulating meds, excerise, etc... 2-3 hours before bed. If only taking 1/2 an Ambien doesn't work, try 3/4 for a week or so, then a 1/2, then a 1/4, then off. The vacation suggestion is excellent if you can afford it. It resets your circadian rhythm (sleep/wake) cycle with exposure to sunlight (your eyes need exposure to stimulate chemicals in your brain) and a re-established bedtime and natural wake routine, besides being relaxing and taking some of the stress out of the process without worries about work or such. Do you have any other issues like restles legs, sleep apnea, or hormone issues that could affect your sleep? If you need further help, see a board certified sleep Dr... regular Dr.s just don't have the specialized knowledge to most effectively help you.
This is the education I've received working in a sleep lab. As always, consult your own physician for help. (I would seek out a sleep specialist myself. You wouldn't believe the erroneous suggetions given to me by regular Dr.s.. even the ones I adore. Sleep medicine is a specialized field. We take sleep so for granted that we just don't realize how much is involved and like any specaility, it requires separate education. Look at how much mis- information regular Dr.s have about gastric bypass for example. They can't possibly be educated in all aspects of our care. Seek out a specialist.)
I hope this helps you some.