No need to worry or uninstall / reinstall drivers. There is no problem. If the external display is disconnected, it is of course just normal that system only shows one display.
If you have updated the display driver when external display was not connected, it has restarted itself after update procedure, noticed that you are only using your laptop's display, thus showing accurate de facto status: only one display connected.
I repeat: no problem, no issue, no actions needed.