Dave, they'll probably suggest either taking meds for ~year that will dampen the effect of your thyroid to see if that takes care of the situation. If not, they might suggest a treatment with radioactive iodine that will kill off some or all of your thyroid. You'd then have to take synthetic thyroid for the rest of your life.
Think of your thyroid like the motor that runs you. It's running high, therefore your pulse is probably high, you may have lost weight because your metabolism is higher, you might have diarrhea. Basically, everything is running fast. People with hyperthyroid sometimes are a little...cranky, too. My mother had this 20 years ago and it came back. She just had to do the radioactive thing. They didn't warn her first that she'd literally BE radioactive for several days afterwards and would need to be quarantined.