I was on high dose Prozac (120mg) for nearly 5 years, for OCD & depression, and I had no w/d symptoms coming off it. I simply stopped taking it one day when it didn't seem to be helping any more and I'd gotten all I needed from being on it. I've also withdrawn with a slow taper from high dose Effexor, an SNRI, which wasn't too bad.
In any case, it really depends on the specific SSRI, because they all work slightly differently and have varied half lives. Because Prozac lingers in the body for so long, w/d symptoms are virtually unheard of. Also, the longer you're on an SSRI, the more receptor down regulation you have, and that down regulation is believed to be responsible for the therapeutic effects. This explains why it takes weeks for SSRIs to start working, and why their effects continue after you've stopped taking the drug.
SSRI dependence isn't necessarily something to be worried about, especially not at the cost of your mental health. I don't know how severe your panic disorder is, or how much MDMA you used/abused that triggered your condition, but I do know that longer-term SSRI treatment of anxiety disorders is quite safe and more effective than short term therapy. You feel better now most likely because your SSRI has started having significant effects, and if you stop treatment too soon your symptoms could return. Listen to your Dr; there's a reason he wants you on the SSRI for a year.