Hi, yes it is one of the signs for depression. How long have you been feeling like this? Do you feel sad or blank? Do you think you have lost interest in activities which you used to enjoy earlier? Do you have difficulty in concentrating? Has your appetite increased/decreased than before? Do you get excessive negative thoughts? Do you prefer being alone? These are important questions before coming to a diagnosis of depression. If the answer is yes to most of the above questions and it has been going on for quite some time then you should consult a psychiatrist soon.

As already answered, this very well could one one of the symptoms of depression, but there are many medical causes for the same too like hypothyroidism, anemia, diabetes etc. Kindly consult a physician first to get yourself evaluated for the same. If there is no underlying general medical cause, then meet a psychiatrist in person for thorough evaluation and management. Good luck.