Hi dear, Good DAy HAshimotos Thyroiditis may eventually develop in to hypothyroidism. You must check your TSH and Free T4 levels. Your pituitary glad is a master gland which controls the function of thyroid through a hormone called TSH ( Thyroid stimulating Hormone) . TSH stimulates thyroid hormone production and favours growth of thyroid. If your thyroid is not producing enough hormones, then your pituitary produces TSH in excess to stimulate Thyroid gland. However, in conditions where your thyroid produces excess hormones, pituitary production of TSH is reduced. Hypothyroidism sometimes can cause weight gain and in extreme cases, can cause vocal cord edema etc. These can cause sleep apnea. However, the commonest cause of sleep apnea is obesity. When you have sleep apnea, you tend to snore during sleep and your sleep breaks and you may even have apnea ( chocking). In the sleep you may not be aware of it. This leads to lack of good quality sleep and you may not feel fresh in the mornings and may feel fatigued. You may even fall asleep while watching TV, reding or while driving. You may need a sleep study and there are effective ways to treat sleep apnea. Please discuss with your doctor.