Living in the now
Okay, so this may seem like an old cliche, but it is a well-known phrase for a very good reason. We all need to stop living in the past or the future and just be in the present. Being thankful for what we have now, who we are as people, and not worrying about what the future may bring.
These kinds of thoughts can just drive a person crazy, so they need to be able to take a step back and be in the moment. Enjoy whatever you have, and who you are with, and be grateful for it. To put it simply, it’s just not mentally healthy to be thinking about something you can not change or control.