I sleep well, my vitamins /thyroid normal. but i feel fatigued throughout the day and i feel sleepy. sometimes i get dizzy spells?

Tired and dizzy. Please see your doctor. He/she may look into things like sleep apnea, insulin resistance, etc. If you are overweight or don't exercise this can raise the probability of the above. Peace and good health.

Agree with Dr Seif, as a sleep disorder needs to be considered. Since there are multiple causes of fatigue, including hypothyroidism, but also anemia, emotional issues such as depression, demyelinating brain disorders, poor conditioning, etc., worthwhile to explore other etiologies. Daytime sleepiness and feelings of dizziness may be initial signs of narcolepsy. Discuss all of this with doctor.