Iphone update ios 6.1.2 made my battery drain

Since I updated to the new ios 6.1.2 my battery has died extrememly fast and now it won't charge past 1% and if I take it off the charger it will die on me and I will have to wait for it to come back on and it still will not charge....anybody know what I can do to fix this? I've already restored the phone and everything and it didn't fix...is this just a problem with the update or is my phone messed up?