Don't panic, go through this checklist
How to Fix New Second Monitor Not Detected Issue in Windows
Second monitors offer an easy and convenient way to improve productivity or enhance your gaming experience. Not only that, it also gives you a larger canvas that acts as an additional workspace for general multitasking.
Connecting your second PC monitor is usually a plug and play process, but in some cases, Windows 10 may not be able to detect the monitor. There are a few basic causes of this issue, such as a damaged or defective cable, your PC does not support the second display, you have an outdated driver, or the display drivers cannot handle the second display.
If your second monitor is not detected, you can use this guide to troubleshoot your monitor.
