How difficult is quitting ssri's/zoloft?

Taper. As long as one tapers off under medical supervision it is usually tolerable. Tapering too fast or stopping cold turkey can lead to serotonin discontinuation syndrome. Paxil (paroxetine) is one of the more difficult to take off. Most people do fine with a taper. Take care.
Difficult. Patients are usually on these medications for anxiety/ depression symptoms. It does alter the brain chemistry, so to allow the body to slowly adapt to not having it is tricky and can take months to years. You could feel a rebound of the original symptoms and/or other effects if you stop too quick.