I really hope that you don't leave...
So many people are getting targeted on here and having their stuff rated down and it seems to me you're getting hit a lot because you're pretty much the best author on this site.
I know its tough, one of my stories just got rated down from a 5 to a 4 too... At first I was upset but then I decided it really didn't matter because no one was sending me bad reviews so it must have been a troll.
It is sickening that people feel the need to come here and target writers as amazing as you, and I understand your decision to leave totally but just remember there are people here who love your stories and want to keep reading and rating them and feel just as awful as you do when someone rates them down.
If you decide to stay I know a lot of people, me included, will be so thrilled, and maybe its about time we all started putting less importance on stories going green, a troll can take that away all too quickly but it means shit about what your readers think. Your readers love you and your stories and we're all going to keep reading them whether they're a five rate or a four rate or even a zero.
I hope you get better soon -hugs-