Battery Problem

My battery dies soooo quickly. I've had it since the day it came out and have only been having this problem recently. I charge my phone a lot until it is fully charged so it's definitely not me. After a few texts it will jump down to 3 bars, then a few texts later 2, then a few texts later 1 bar then soon after it will start to die. If I send a picture message or even just take a picture it automatically goes to 1 or 0 bars even if it's fully charged. I don't use the internet and I def text a lot more then I call, but when I do have the opprotunity to call I don't have battery on my phone! Why am I having this problem and what should/can I do because the battery dying quickly is very inconvenient for me.