Hello 'pittpensgogo',
<<items in my "Watch List" changed to a different currency than U.S. Dollars. How do I change them back?>>
By logging out of the Canadian ebay where you have somehow ended up and returning home to the American ebay to log back in where it will all look normal again. Go to:
Come back and see us any time. You'll know it by the little Canadian Flag at the top of the page and the address bar will indicate ebay .ca instead of ebay .com
Hope you had a nice visit. 
