That sounds awful.

I don't know it. I never used any antidepressant.

Maybe you can use some herbal remedies that work like antidepressants. But it might be due to a serotonin receptor that is blocked with Zoloft and not with Lexapro, if I remember correctly. Blocking a serotonin receptor is unusual, but it's why atypical antipsychotics are also (like) antidepressants. It's the weight gain 5-HT receptor (probably).

Edit:
I didn't remember correctly: the above is about Prozac, not Zoloft.