My 5 yr old son has hypothyroidism (tsh at 6.15). he's become very emotional, very hard on himself, and insecure. are these symptoms? what can i do?

Yes they can be: Anxiousness, and anxiety could be symptoms of hypothyroidism. You want to make sure that his synthroid (thyroxine) ( if he is on it ) is therapeutic enough to supress the secretion of TSH from the brain. With a level of 6.15 it is really just barely in the hypothyroid range. So close follow up and monitoring is important to prevent cognitive deficits caused by hypothyroidism.