Your reports are suggestive of auto immune
thyroid disorder with hypothyroid status. It means that because of some reason your thyroid has been damaged by your own immune system and it is functioning suboptimally. Right now it is producing adequate amount of hormones but at the cost of its enlargement. You may need to take thyroid replacement tablets such as thyronorm in minimal doses
Next Steps
Consult nearby ENT specialist or endocrinologist for appropriate dosage of medication