How can we tame this negative thinking.....

A way that I have found to look at all of this untamed anxiety that is running around is to, not let go but to become aware of this thinking that is going on.
The majority of it is negative.
It wants to keep you in it's negative loop.
It enjoys being in control and keeping you stuck.
There is research concerning all of this negative thinking and how it affects your heart, brain and other organs.
So we need to become experts at becoming the observer of our inner voice or squirrel on the wheel and then these negative thoughts will become less intrusive and start fading away.
They will try to rise back up and take control again.  Just step back and say humm, there you are again.  I see you, I feel you and I am going to not resist what is going on.

LENS neurofeedback can help you to get a grip on your over active brain and thought processes.  Give it a try.