1. Realize its effect on your health.
No matter how bad things appear now, it is certain that no one wants to die prematurely, although some may feel so much pressure they may believe that is the only escape.
I am pretty sure you have dreams that are unfulfilled which you will like to live to see their fulfillment. This should be a driving force.
A closer look at your past life will tell you the harm negative thought has caused.
So, there is no better time to quit than now!