Problem with Samsung Galaxy S5..Any suggesions?

Hi..I purchased a Samsung Galaxy S5 few months back. During the first 3 months, the phone was working fine. For the past 1 month, I have been facing a lot of issues with the phone – The battery of the phone gets drained off very quickly and has to be constantly charged. Moreover the Wi-Fi of the phone suddenly stops working sometimes. I am left with only two options - using the forget network option or to reboot the phone. Rebooting the phone every time has become a pain. Kindly suggest what should I do?