Cassie, I have Firefox but changed over to Internet Explorer 9 and encountered the exact same problem.
I, too, went into my history and clicked on a link to a discussion group on which I posted recently--so it took me back to where I was already logged in.
Ahhhh, great minds think alike. LOL
Age 67, 5 feet tall
Highest weight ever in the fall of 2010 246 lbs.
FitDay starting weight 1/17/2011 240 lbs.
Weight 12/18/2013 on my doctor's scale 231 lbs.
Weight 1/2/2014 on my new home scale 229.4
Weight 3/9/2014 225