I do not know where your notes are without having access to your device. I'm assuming you're using an iOS device. Having said that, you can login to iCloud (I'm assuming the notes are associated with iCloud), and then check to see if your notes are visible online. If they are then they can sync to your device. Reboot your device or logout of iCloud and then log back in to iCloud on the device. You can also try disabling and then enabling the toggle next to notes in the iCloud settings.