From working in a pharmacy for the last 4 years, I have gained much knowledge of these drugs. Melatonin is ****e - it has been proven through trials to be ineffective as a hypnotic (won't knock you out). As far as hypnotics, the main groups are the benzodiazepines (temazepam, nitrazepam, lormetazepam etcetc.), and the newer "Z" drugs; zolpidem, zopiclone, zaleplon.
Of these drugs, zopiclone is the most safe for long term use. In long term use, the risk of addiction is present though the harm is much less than benzodiazepines such as the notorious temazepam.
when you go to a doctor, chances are you will be prescribed temazepam or zopiclone. In your circumstances - the use of zopiclone only once or twice per week is perfectly safe and harmless. Don't believe what people say about sleeping tablets and the dreaded "addiction" - this is an overexaduration (like use of steroids associated with instant testicular atrophy!!).
Regarding the side effects - these are perfectly normal, just dont drive a car afterwards!. Zopiclone only has a strong effect for 6 hours, so driving a car will be fine the next day.