I have only had this MacBook Pro for a few months. I have been using my iPad lately. Today for a training for work, I disconnected my MacBook from charger, and placed in my bag pack. (Oakley bag, with padded slot for laptop). A few hours later (my bag had been sitting on floor) I pull out MacBook and it is very hot. And battery is down from 100% to 74%. What would cause that? Why did it not stay asleep? Thanks.