Reading between the lines, it would apear that your gp may actually be treating you for depression, or at least the symptoms of depression/stress.
Does he realise that you are a pilot, and the implications that this holds for you (and your passengers)?
You need to talk to an aviation doc about this, but I guess you may be grounded.
Previous threads suggest that SSRI's are incompatible with flying, but don't suddenly stop taking them without expert advice.