From what I understand, from a little research yesterday, your account does a "soft expiration" after 90 days, meaning that the name is available and someone can create a new account with the name, and yours would no longer be available. The account is still there, and can still be used, until it's hard-deleted. This only happens during occasional maintenances and such. After a long period of time, it's pretty likely that your account would be gone for good, but it's certainly worth Slaynish checking.