Unexpected app crashes and screen issues on iPhone 11 after visiting a free book website

okay so this is going to sound dumb but I when on a free book website and it said that I got a virus and that I needed to handle it immediately. I didn’t think much of it so I kinda didn’t think To much about it. But then my phone started acting up, (I have the 11 so I know it’s kinda old) my phone has been having like a mind of its own. My apps. Will crash, it will make my screen MAJOR crash and it’s like something controlling my screen to annoy me or something. I even have having a hard time typing this so sorry for errors. Please help idk what else to do.

[Re-Titled By Moderator]