Hi Hackedoffandhangry,
Thanks for reaching out to Apple Support Communities. It sounds like you're having an issue with an alert on your iPhone. We're happy to help.
Without unauthorized modifications it's unlikely the security of your device would be compromised. If needed, you can view more information here: Unauthorized modification of iOS can cause security vulnerabilities, instability, shortened battery life, and other issues
However, we recommend starting with the article here: Recognize and avoid phishing messages, phony support calls, and other scams
If the issue started after browsing, we'd recommend clearing your website history: Clear the history and cookies from Safari on your iPhone, iPad, or iPod touch
If it started after downloading a third-party app, test using your iPhone as you normally would with the app removed: Delete apps on your iPhone, iPad, and iPod touch
We also recommend checking for any spam calendars added to your iPhone: Delete spam calendars and events on iPhone
Also, do not enter any of your Apple ID information via the pop-up. Change your Apple ID password and ensure you have control over your account with the steps here: If you think your Apple ID has been compromised
Best!