People have thought this before, but it's usually not a hacker. The easiest thing to do would be to reset your password, but if the email address you used to make the account isn't a real one you might be hosed.
Often, your password gets messed up when you try to make a new account while you're still logged in to your old account (this happened to me when I was setting up the debating profiles). The password might have reset to the one you set up for the new account, but I'm not sure.
Regardless, this is why it's very important to use a valid email address when making your account so that you can retrieve your password when something... odd happens.
