Write your feelings down, then sit on them.
When you feel flustered or otherwise overwhelmed, write your feelings down, and then sit on them.
When you get emotional, you also get irrational, your feelings can lead you astray from clear thoughts. It’s why a buffer is important. However, there may also be something in the feelings. Hence the need to write them down for later use, if you need them of course.
By the time you need them, you may well have calmed down enough to not need them. Then you would have been worrying about nothing at all.
This is especially true of thoughts that keep you up at night! The writing part lets you see your thinking more clearly, and helps give perspective that can help you get back to sleep.