Help Battery messing up


Ever since i updated to Gingerbread, My phones battery has been going down hill. Sometimes when i turned it off at like 39 % of batter, ill turn it back on and it will have 23% of battery left.
At this point i cant wait till my contract is up and i can get a new phone
Also my lock button is stuck so my phone will not unlock at times. i will have to hit it up against my hand for the lock pattern to come up