Try eatting more red meat to deal with low haem iron and Vitamin B12 deficiency.
Try exercising and having a regular sleep schedule.
If that doesn't work and you don't want to go to the doctor, get a Vitamin B12 injection (for pernisious anemia)
If that doesn't work, then go to the doctor because chronic exhaustion is very treatable.
(If you want to self medicate, have you tried adderal or methylphenidate?)