Hi TRINIDADTEXAN. Welcome! Gosh, those are high medication doses.....I take 100 mg of Zoloft daily and whenever I've tried to go above that, my anxiety and agitation has become worse. So I can only imagine how extreme that must be at a dose of 300 mg per day.......Having said that, I know several people personally who take 200 mg of Zoloft per day, and a couple of who take above 200 mg per day, and they do just fine. It definitely varies a lot from individual to individual.
It is always advisable to taper down slowly when seeking to reduce a dose of medication. What did the new doctor you saw today suggest? I would strongly recommend that you contact a doctor again to discuss a tapering schedule. If people stop their medication abruptly - or reduce their dose dramatically overnight - it can be extremely unpleasant and even dangerous. I really hope you will contact the doctor to discuss where to go from here medication wise.
Let us know how you get on! Wishing you all the very best