Open Bitdefender and check the Shield icon. It should be green and accompanied by the message "You are safe."
The Bitdefender Shield provides real-time protection against a wide range of threats by scanning all installed apps, their updated versions, and new and modified files. I do not recommend you to disable Bitdefender Shield, but if you have to, do it for as little time as possible. If Bitdefender Shield is disabled, you will not be protected against threats and the icon will turn red.