See a doctor to make sure there isn't a medical reason for your flood of negative thoughts.

As soon as it starts happening, actively focus on something else more pleasant or absorbing. Think of something that interests you and take classes in it. Learn a new language. Study bugs. Knit. Set a goal and focus on it, like, "I want to get my real estate license". I want to become a real good birdwatcher. Whatever. The central point of this advice is to think about something else.

Here are a few that changed my life for the better:

PART 1

1. If you can't have what you want, think about something else.

You will be happy with the new thing too. Your happiness is your responsibility. Don't mope around. Move on! It's a big world out there.

2. If I keep going in this direction, I'm bound to get where I'm headed.

If your marriage is in trouble, should you start having lunch with that cutie at work? Be honest with yourself and identify your goals. Maybe you should end the marriage but don't fool yourself with, "The affair just happened!" No, it didn't. Little steps add up to big consequences. Identify your goal and be honest about the steps needed to reach it.

3. Simplify decision making.

--When making a difficult choice, choose the option that leaves the most options open afterwards. Trim the branches before cutting down the tree.

--Only compare two things at a time, choose one, and never consider the unchosen one again. Compare the winner to Option 3 and pick one. Etc. The last one standing is the winner.

PART 2

Bad things happen. People hurt you. A job might suck. Whatever. When tough things happen, you essentially have three choices:

1. Stay feeling miserable. You can keep trying and trying to fix it and stay miserable because nothing ever works or stop trying and wait in a state of misery for the situation to fix itself.

2. Figure out a way to find honest peace with the situation. That doesn't mean never thinking about it and never feeling sad but when you do feel upset you actively change the focus of your attention to something else and get back to peace and fun as quickly as possible. In short, don't mope around thinking about it all the time. Think about something else.

3. Leave the situation completely. And think about something else.

For me, Option 1 is not an option. At some point in my life I decided staying in a situation where I'm relentlessly unhappy or stressed is unacceptable. That one decision improved my life dramatically. The tricky part is knowing and accepting when nothing is working. You don't want to quit too easily but trying over and over fruitlessly or waiting for too long is harmful.

Option 2 can work. I was deeply hurt by members of my family. I was in a state of "leave or stay?" for a year but I was able to find peace with what they had done. Its not like I never think about what they did but I chose to accept they are flawed in a way that led them to betray me. They have other wonderful qualities that has made it well worth my while to keep in contact with them.

Option 3 also works. I been where things are so upsetting and irreparable that I had to leave. I didn't look back and am happy with that choice.

A crucial part is to think about something else.

Good luck!