I have a new iphone 5 and it already has problems?

Okay, so i bought my iphone 5 a while back and the wake button developed a fault so i took it into apple yesterday and they replaced it. When i wake up this morning from my phone being on charge it was off and wouldn't wake up to the wake button or home button so i tried turning it on and rebooting it this took about 10 minutes to work! The battery also seems to be decreasing a lot quicker than my previous after using it for 10 minutes i've lost 3% where as i usually would have lost none. My Wi-Fi also keeps switching to 3g? If anyone has any answers to my battery issue or 3g they're welcome if not should i just go back to apple?

Go back to apple

If its under a year old take it back to apple and they'll replace the phone for you

For the Wi-Fi go to internet settings and disable the 3g while using another internet source, yes it sucks but this is the way in Iphone 5.

Also try to give your phone some space, turn it off, charge it to %100 and then try turning it back on. The battery seems normal for IPhone 5's