If you don't have any data, such as your posted creations, the cause could be the following:
- Whether you've logged out or not
- Whether you've logged in with another account
As such, please check to see if you're logged in and if you're logged in to the right account.
If you happened to forget the account information of the account you wish to log in to, please take a look here.
https://www.pixiv.net/support.php?mode=faq&service=pixiv§ion=360002512134