Hi Jorobbo,
I just wanted to say "Welcome" to the NeuroTalk Support Groups.
Unfortunately I don't really have much to suggest regarding your symptoms. Hopefully others will post.

Regarding the Sertraline, from what I know any discontinuation symptoms usually occur from about 7 days and usually are gone by a month. A few of those things you describe could be related or could be related to migraine as well. Sounds as if you have a couple or several issues at once.

Wondering if you have migraine.

If your toes are cold but rest of foot is warm you'd wonder about a vascular problem but it's in both feet. No blood sugar problems?

joint pain, nerve pain, temperature change in toes both feet, itch [without rash?] fatigue, parathesias. All suggest inflammatory condition.

I'm sorry it's all become so much worse for you the past few weeks, maybe exacerbated by discontinuation of the zoloft, but maybe not. I hope some of it subsides for you in the next couple of weeks though. Ask for more help from GP if it doesn't.