are indeed a symptom that is associated with withdrawal
of the drug.
Taken from the consumer information for zolpidem (Ambien):
"Do not stop taking this medication suddenly without first talking to your doctor. You may need to use less and less before you stop the medication completely.
Withdrawal symptoms include behavior changes, stomach pain, muscle cramps, nausea, vomiting, sweating, anxiety, panic, tremors, and seizure (convulsions).