Is it the doctor recommending anti-depressants?
If other physical problems are already ruled out then depressants may work but they ALWAYS need to be used in conjunction with counselling. I can't remember the sites that I checked out a year ago but one thing I remember several places saying was that childhood depression is more easily cured than adult onset depression.
I was on depressants once as an adult. They didn't cure me but they did halt the racing thoughts and downhill thinking. Depressants usually take a few weeks to really kick in so don't expect miracles in a week. The net has a lot of websites about medication. Whatever particular medication is prescribed spend the time necessary to read what you can about its side effects and results.
Sorry if I'm a little wambly at the moment, not enough sleep and too much caffeine.