There is a difference between having a bad day and being clinically depressed.
With a clinical depression, a number of specific criteria must be met in order to receive a diagnosis. Daily functioning is often impaired and symptoms last for 14 days or more. You can’t just ‘snap out’ of a clinical depression as you might be able to if you were having a bad day.
Whether your low mood has been ongoing, or whether it just today, include a mix of activities in your day to give yourself a feeling of achievement and enjoyment. Also, give yourself the space to be sad. To cry. To get the rest you need.
Getting better is often a mix between pushing ahead and being kind towards ourselves.