Strange small screens with Clock and WiFi symbol appearing

You haven't been hacked and I'm not sure why that popped up, but I recommend a Forced Restart of your iPhone. See this link to see how to do that --> Force restart iPhone - Apple Support

If this doesn't resolve, use the Contact Support button at the top of this page to communicate with Apple directly.

Please either post a screenshot or take a photo and post it so we can see what you're referring to.