Iphone SE battery life

Hey, im using iphone se for like 2 weeks and i have impression that after about week my battery life have decreased much... Im anxious about it because of the previous iphone i had. After all tests i made, i found that my battery is lasting 5 hours in use (mostly safari, sometimes facebook or pokemon go). Is it a normal usage time or not ? Im not using background refreshing or localization services when its not necessary. Im thinking about exchanging it or "repairing" cause i have impression that in first days the usage time was like 9 hours.