Logging in one day, to suddenly find a level 1 account is quite shocking! However, have no fear, your account was not reset, rather the mobile app created a guest account for you!
Things like phone updates, Facebook account updates, Google/iTunes updates are some common causes of for the mobile app to sign your device in as a guest account instead of their regular one.

To fix it, navigate to the MORE tab, tap on MY ACCOUNT, then select LOG OUT. You’ll be prompted to log in with your account details.