Overeacting?

In september I had to quit my job. One day, I found a whatsapp group of colleagues from work, in this group, they all joked about myself, writing I was a "crazy" and "fat bitch", and that also, i was a "useless person". Now, I'm facing various months of unemployment, and I'm constantly in therapy. ¿I should have stayed in my work?, ¿it was a "good" decision to leave that horrible people?... my mental health is not the best due to this situation.. be frank.