Hello... I understand your situation, based on the history you have given I think you should know that human body require atleast 6-8hrs of sleep.. Without that a person will be irritable, drowsy, difficulty in recollecting recent things if severely sleep deprived, peeson feels easy tiredness... So I suggest you to do some morning brisk walking, meditation and yoga to destress.... There are certain hospital which has sleep clinics who can address your issue kindly visit that center... Good luck...

Your age is the most important criteria. If you are adolescent, than try exercise and Take multivitamin once daily after food. If you are young adult or adult, than clinical examination and laboratory investigation are necessary to rule out chance of diabetes or thyroid disorder or any other chronic illness related to lethargy feelings.