iPhone 6s taking forever to charge and battery draining very fast

I got a new iPhone 6S, 3 days back. It seems like a great phone with lots of great features but I am seeing the battery drain very fast. On standby alone I am losing around 2% an hour. Overnight drain is around 20%. And charging the iPhone is taking forever. It took me 55 mins to get from 74% to 100%. My previous iPhone would charge faster with the charger provided with the phone at a 1% per minute rate. Is anyone running into the same issue?

I have not used the phone as much. No photo taken, only whatsapp downloaded, made 3-4 phone calls in 3 days. I don't know why battery is draining so much. And the time it takes to charge is awfully long.