Hi @Dragoneyes!
We are sorry to hear that your photos have disappeared. We would primarily go to the Gallery app > 3 Dots at the top right > Trash can. Look here if your photos are there, and you will be able to restore them.
Should they not be here, it could be that your photos are synced with a cloud account that has now lost sync with the phone. If you know which account it is, you can go to settings > Account and backup > Manage account > Tap on the account > 3 Dots at the top right > Delete account. After this, you press add account and log in again, and the sync should be activated again.
/Daniel
