Hi Tale
Welcome to HealingWell and the Depression Forum.
Zoloft has a half-life of about one day. That means that for every day that passes without taking the medication the level in the blood falls by 50%. After one day the level is reduced to 50% of the original level, after two days to 25%, after three days to 12.5%, and so on.
When you stop Zoloft too rapidly a withdrawal syndrome may develop. Symptoms you may be experience are nausea, tremors, lightheadedness, muscle pains, weakness, insomnia, and anxiety.
I agree with the other members that it most likely was the medicaiton withdrawal that caused your sx but please do talk with your physician if you continue to feel bad. It may take you a bit of time to get back up to where you were before you went off the medication suddenly.
Again, welcome.
Kitt