This is something I have struggled all my life. Continous rambling in my brain about the past and the future. I recently came across this nice article where a monk who is a smoker approaches his master on advice to quit thinking, the dialogue between them has a lot of wisdom.
Whenever I want to quit any bad habit, I inevitably find myself thinking all the future things I need to do so that I have the will power to not do it again. The story in the article points out the rubbishness in this thinking. All we have is the present. If you want to do build a habit, the best thing to do is do it now, and now is eternal. Same applies to letting go of bad habits, you just let them go - now.
I don't remember where I read this, perhaps it was in the book "Sapiens", it was along the lines of - humans started future planning when we settled down as farmers from being hunter gatherers. The hunter gatherers lived in the present, you didn't worry about whether you will have food to eat the next month. You just worry about today. The moment we settled down into farming, then we had to make sure that food was available throughout the year. Because we had lost the privilge that hunter gatherers had where they roamed around place to place scavenging for food.
This habit of "future planning" has hijacked our brains, that we always keep future planning without enjoying the present.
We are here today in 2023, lets be practical. We have to plan for the future. 10 years ago, my family lived month to month on a meagre income. Today, we have enough money to survive a year (barring medical emergencies), and I would like to plan my future so that I don't end up in the situation where I was 10yrs ago.
So how do we future plan without detaching ourselves from the present ?
I think the answer lies in setting up good habits that fades into the background while you enjoy the present.
Wealth Just setup a system where x% of your income every month goes into savings and investments (keep it simple - invest in nifty50). Over the long run (say 10-20 yrs), you will be wealthy and fine.
Health Again, setup a system that can run in the background. Ex: Exercise for 60 min every day by going to the gym, let the habit fade into the background. Don't use tech after 8pm so that you can sleep well and sound. Learn cooking, so you eat homemade food which is healthier.
Happiness If you have wealth and health, then the missing ingredient is just good relationships. And finding a vocation that you you love. This is basically naval's life formulas
tldr; There is an surprisingly easy way to stop overthinking, which is just to stop overthinking - now