Ambien does stop working after awhile due to what we call tachyphylaxis, the process in which your brain becomes tolerant to it. However there is no withdrawals associated with stopping it. While you were taking it, you did not cure your insomnia, which is the reason you needed to take it to begin with, so now that you stopped taking the Ambien, you are having the problem again.
There has to be a reason for your sleeping disorder i.e. anxiety, depression, sleep apnea, stress, use of stimulant intake late in the day (caffeine) or lack of intellectual stimulation during the day. There are multiple medical, psychological, dietary and pharmaceutical reasons for poor sleep. You may want to sit down with your primary physician and talk about what can be changed in your daily routine, diet or medications. Discuss the concept of "sleep hygiene" as well. Good luck to you.
U can take subutex or suboxone they will help with withdrawls i take it and it DOES indeed help with wothdrawls hope that helps....