Unfortunately the only way to tell if something will work is to do a trial of it. I was in a similar situation where I wouldn't try the SSRI given to me for months. It wasn't a miracle worker, and I ended up on a different prescription, but trying it still allowed me to move forward and eventually get to what I needed. I know the cloudiness sucks ! Along with all the changes, but in the long run its probably for the best to give it a shot.
It really doesn't matter, because our experiences have nothing to do with how it will affect you. Your experience with Zoloft, for example, is probably a lot different than that of the people on here who have taken it. So the only way you can tell how any drug will affect you is to take it. The only way to avoid that is to fix the problem through therapy, which isn't easy but I hope you're trying. If it helps any, Lexapro has a reputation for having fewer side effects, but I'm not sure it's really deserved or not. But it does have that reputation.