Just suggesting precautions.
If you did not see self-defense spring into action (as it would if an outside entity opened your GUI from outside) you've nothing to worry about.
If Avast is operating as usual, and nothing was changed, no worries.
Entirely possible to click on the Avast icon in the taskbar by mistake when you meant to click something else next to it and and also Avast GUI can take some time to open on the desktop (two to three minutes in some cases, or, in another user's case, ten minutes). I recall version 17's GUI was very slow to open a while back.
You can test your real-time protection here (and don't worry you are safe to do so):
https://www.amtso.org/security-features-check/This test suite is quite extensive in scope.