My rheumatologist started me on 2,000 iu of vit d for low vitamin d level of 20. could this help me not feel so tired and when should it be retested?

May help: Vitamin D may help, though it is unlikely to be the only cause of your tiredness. You may keep taking 2000 units daily for ever to keep your vitamin D at an adequate level. There is no need to retest. Counter-intuitive as it sounds, exercising may help with tiredness. For good health - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Drink enough water daily, so that your urine is mostly colorless. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Practice safe sex.