I hope you stay with Android and with us

. Here you'll learn tricks and great things about custom launchers, root, roms, themes, modules and much more. BUT. Right now there's a different problem. Rooting your phone will void the warranty and there's always the risk of ending up with an expensive paperweight in your hands.
The responsibility is in Samsung or your carrier hands. Take it to the shop. Most likely they'll recommend you to do a factory reset. But even doing that is their responsibility.
And, of course, there's a chance that you were unlucky and your phone is just defective.
After a major update there are always bugs and some people, as yourself, will have some serious problems. Even that is a valid claim to have your new phone replaced.