OK, so why is it important to keep a journal? Well, as you know, I've got a terrible memory so it helps me to remember days gone by, what I did back then and how I felt about it at the time!
I reckon it also helps you to remember things and it's a very personal thing. You can get lockable diaries which is what I used for many years then discovered online blogs and that has become my journal now!
Getting things out of your head and written down can help you relax at night and drift off to sleep. It doesn't have to be long or detailed, it just has to come out so that you can use the head-space you've just cleared for something else! hahaha
Go on, get a diary and give it a go for a few months... just be careful you don't get addicted!! lol