Someone snatches my my Long Time User name

I am not able to log in this week becuse my long time user name is somehow taken and I am " locked out " untill I choose another? Its been about 6 weeks since I last logged on.
What is going on here?

As new usernames accumulate quickly on our server, we take to clearing ones that haven't been used in 30 days to control memory consumption. Once your username is cleared from the system, it's free for someone else to log in under with a different password.