If you can get your feelings and experiences out on paper, they can become less overwhelming. Looking back through past entries can help you to identify patterns, and give you ideas if you spend some time reflecting on what is keeping you stuck.
Set a timer for ten minutes, and write about your day until the alarm goes. Even if nothing at all has happened, you will most certainly have thoughts in your head that are dying to get out. Offloading conscious and subconscious thoughts helps the mind become clearer, and you calmer.