edit: oh an make sure you let your battery drain completely if you continue to have unusual power behavior. You need to show your battery where the bottom is so it understands correctly where it is now. You should do this soon if you haven't done in already (in the next day or two) and then once a month thereafter. Not too often though, as that will hasten your battery's demise.
THIS IS NOT TRUE OF LITHIUM CELL PHONE BATTERIES.
Nickel-based batteries (either NiCd or NiMH) DO NOT generally suffer from a misunderstood phenomenon known as the "memory effect." As described in Wikipedia and many expert sources,[2] the term "memory effect" has been widely mythologized to describe any and all deterioration of NiCd (and other battery chemistries), in many cases misleading consumers into further shortening the lives of the batteries through over-discharging to "recondition" them.
Lithium ion batteries can be preserved by careful charging and avoiding storing them at full charge. They do not require "reconditioning."
(reference: How to Make Your Cell Phone Battery Last Longer - wikiHow )