Why am i'm tired all the time (started months ago). tiredness all day. i'm active, drink lots of water, eat good, young, good health. depression?

Tired: Yes , depression can give you symptoms of fatigue. However, you should see your doctor for a full physical and blood work to include a full blood count and test for thyroid function

Please have a physical exam first to know if the problem is caused by illness. If not, then please see a Clinical Psychologist with expertise in multiple types of psychotherapy to help you with the tiredness you are feeling. Medication managed by a Psychiatrist may be helpful.