Damn, that was not an easy coming back. Welcome back anyhow!
If you haven't linked your account to Facebook and you uninstalled the app, your previous account is indeed lost.
Go into "settings" to link your Facebook account to be able to retrieve this one. If you still have an error there and cannot link your account, tell me! Because this Facebook related bug will inevitably affect more people.
How in hell were you able to bypass the "choose your name screen"? This is a bug I'm struggling to reproduce. You are playing on iOS right?
I manually gave you back your first name too (you will keep your current unpalatable name for the current game however).