How can I stop thinking and shut my brain off?

Read! Write a journal, do some housecleaning! Do everything you can other than sitting in bed and watching movies!

Thinking is not the issue, it is the stuff you are thinking about. so switch the thoughts. think happy thoughts. Name things that make you happy and make you smile.

It's a bit of a paradox isn't it? The more you try to stop thinking the harder it is. If you're preoccupied with something, preoccupy constructively. Separate what is in your control and what isn’t. Focus on the items that are, and the initial steps needed to achieve them. Then write them down. Writing out your thoughts will help to stop them from recycling in your mind. You'll know you've captured them to revisit at another time. And remember, worrying is either too early or too late.

Sometimes it helps to play little games in your mind, like making anagrams of words or trying to remember how to get to your friend's house by memory.

I can let go of thoughts if I do breathing exercises. If I focus on the inhale and release the thoughts on the exhale. Soon they are hard to hold onto. Then physically the breathing has relaxed me. The thoughts may come back but for the time I am meditating and breathing, they clear.

Have you tried any of the mindful exercises that 7 Cups of Tea offers? These might help you. They are in the self help category

you never can as long as you have a brain, so take advantage of it, don't stop thinking, think think think!

Get active! Meet with a friend, do sports, listen to music, cook a nice meal or do something else whichis fun. Sometimes it is hard to stop doing something but easier to start doing something else.

Do something simple that makes you think so you can't focus on other things. For example, count backwards from 100. Try listening to guided meditations. Write. Pray.

You can try distattion, try doing things that make you happier and feel alive and your brain will just stop throwing thoughts at you if you don't pay attention to the thoughts.