On the main log in page there is a little box that says something to the effect of 'remember me each time I log in' (please forgive me if I can't remember the exact words, I haven't seen this is a while).
Have you clicked that box? Perhaps, if you haven't, this could be part of the problem.
"To insult someone we call him 'bestial'. For deliberate cruelty and nature, 'human' might be the greater insult." - Isaac Asimov