I can't advise about the CAA issues, but I can say that some of the modern antidepressants are astonishingly efficient - if you can tolerate the side effects. Fiery indigestion, tremor and disrupted sleep-patterns to name but a few. They are supposed to fade into the background but the timescale is all important to anyone with a critical job. What is certain is the need to get things right; a depressed mind makes a dulled brain. Depression really will lower processing power.
First and foremost, is your depression justified? That is to suggest, 'I'd be crazy not to be depressed'. Life hands out some cruel challenges and quite rational minds often buckle under the strain. To be sure about the validity of the need for treatment is a tough decision and perhaps one of the most important functions of qualified counsellors.
Hopefully someone with CAA regulations will join the thread, but do be aware, once on a suitable course your whole viewpoint will change incredibly quickly and with it an increased ability to do battle with life.