Its okay nothing to worry about this. Wait for the next update to come which will surely improve the performance. Till then you can do one thing i.e. battery calibration.
Calibrate your battery by discharging your phone to 0% and then plug in the device until it gets full charge. I am sure battery calibration will work for sure. (For better functionality u can do this at night when not in use, by putting the phone in flight mode.)
