AT&T Automatic Update messed up my Galaxy S4

I hope I didn't screw up but yesterday I recieved a text message that my phone was about to update and not to turn it off until finished.  The screen went white for the longest time and the phone became very hot.  When the update was finished, all my screen colors and fonts are different, many options have changed.  The settings functions are different, my apps are moved around and don't operate the same.  The battery drain is terrible.  I left for class this evening with a fully charged battery, used the (poorly functioning) flashlight app during class, which I normally do with no drain, and it killed the battery w/in half an hour.  There are now ads appearing on screens (like the flashlight), very distracting.  Is there anything I can do to reverse this, short of factory reset?  I'm not that techy 🙂