Maybe you’re having dinner with a friend and all you can think about is your to-do list. Or perhaps it takes 30 minutes to send an email because you keep questioning how to word each sentence.
There are several reasons why our brains feel cluttered sometimes. Depression can cause us to ruminate on the past. Anxiety can cause you to worry about the future. Traumatic experiences can cause you to always be on the lookout for danger. 
But a diagnosable mental health condition isn’t always the culprit. Having a stressful life or a busy day can also lead to repetitive and unhelpful thoughts.
Regardless of the reason, it’s tough to feel mentally strong when your brain is filled with thoughts that aren’t helpful.