I think my iPhone has been hacked

Your iPhone has not been hacked.

Perhaps someone knows your Apple ID and password?

If you think your Apple ID has been compromised - Apple Support

Unless, either of the following are true, your iPhone has not been "hacked:"

• It was jailbroken
• Someone had physical possession of your phone AND knows your passcode (or looks like you) & Apple ID credentials.

I second @MooreD10's suggestion that you change your Apple ID password ... as soon as possible!