Iphone 6 hacked?

hi, i believe my iphone may have been hacked. I was recently at the store one day and i looked at my phone and it said activation required on the lock screen. I went to go unlock it and it made me reactivate my phone, like what you normally do when you first get the phone. After that happened, my phone has been getting hot When i dont even use it, and i dont have any apps open because i close them all when im done. Another thing is is that my battery drains a lot faster than normal, and i get occasional weird text messages from random emails/numbers with random letters in it asking me to open up a link. Something else that happens is my finger id doesnt seem to work all the time, like everytime i put it in to unlock my phone it says try again, then i deleted the fingerprint and tried to put it in again but it wouldnt let me go all the way through. I was wondering if it was hacked, and how i could unhack it. Thanks 🙂