Iphone opening wrong app; mind of it's own, or am I being hacked?

Here is what happens most often: I receive a message notification (regardless if it's from another iphone or not). I click on the notification to open the message (from the locked screen). The clock app opens instead.

Another weird one: I'll open an app and in the top left corner it shows me the last app I was in...but I wasn't in another app, they were all closed. In fact, it is often an app I haven't used in a very long time.

Is my phone hacked??