IPhone charging pissing me off?

My iPhone 3G isn't charging. At all. I've charged it Over night 3 times and it's stil in the under 20% zone. It doesn't have the battery percent option. When I plug it in to the wall it buzzes of silent and chimes when it it's on silent but it doe t charge. The charger is the only thing keeping it from dying out. It's pissing me off cuz I need to go do stuff and icant take my phone.