I lost my account somehow

Well after taking a break from league for about a month, I logged back on to the game, and immediately a notification popped up telling me to update my launcher. I did as the message instructed, following the message to an official download. After downloading the "Update" i logged back in to the client and was met with the normal "Insert username and password" which I did for my account. However to my surprise after logging in it said choose a summoner name. After entering a name (Different from my previous acct) it let me in, with a whole new account! If you search my account in game, (Vaeiful OBVIOUSLY) it will show you my real lvl 29 account with Aurelion sol as highest mastery, Veigar 2nd, and Kayle 3rd. Any help? I spent a lot of time on that account. Thanks :-/

-As Always Vaeiful