simple home check to guide you.
take you temp every morning you wake up for one week, if you temp is less than 37 degrees c, then you could have underactive thyroid. try adding in kelp tablets as they have iodine, also restrict broccoli, cauliflower, strawberries and peaches (nectarines ok - weird!) as they can interrfere with iodine absorbtion.
best bet, go to dr's and get a check.
good luck!