Accounts are only deleted manually if they have been inactive for 2+ years or if it's an account with 0 minutes of playtime after a few months; neither of which seems to be the case for you, going off your forum's join date.
It is likely that you have not played since there was last a massive password wipe/reset, which required all accounts to reset their passwords to regain access to the account again. Assuming this is the case, you may reset your password via playerdex; and remember not to copy/paste the password, as that may copy over an additional space which could invalidate the password.