If some (or all) of the graphs on your dashboard(s) disappeared, it's possible that your account was set to use the Old UI. Some of our newer graphs (like pie charts, donut graphs, and number panels) are only supported by the New UI.
Once the New UI is re-enabled, your graphs should be available. You can do so by clicking the User Menu -> and enabling the "New UI" toggle:
Please note that if you made some irreversible changes to your dashboard(s), we can retrieve an older version of the configuration for you. Please contact our support team (email@example.com) and provide the date (approximate) and dashboard(s) you wish to restore.