It can be. It can also be caused by medication, if you're being medicated for your depression antidepressants often cause this problem. It can also be caused by nutritional deficiencies, especially in the electrolyte minerals such as magnesium and potassium. It can also be caused by something you did that might have overworked a muscle. Lots of things can cause symptoms. You say you are depressed -- have you been diagnosed with that? Are you maybe feeling sad about something, which is different than having depression? Have you seen a psychologist for it to get it diagnosed and treated?