I requested a name change a few months back by PM'ing Theymos directly, and I got no response.  I seriously doubt Theymos would let OP change his username given that he just registered two days ago.  Just create a new account, OP.  And maybe request that Theymos delete the current one. 

If Theymos doesn't delete your account, just don't log into the one that has your e-mail in it and eventually it'll fade away--and hopefully you won't be bombarded with spam.  Good luck.