Lately I've noticed that my MacBook consumes a lot of power in sleep mode. I've also noticed that it sometimes turns itself on after a couple of minutes even when I've turned it into sleep mode (always using Alfred, if it matters). Like today, I went away from my Mac at 4 p.m. and turned it into sleep mode. The battery charge was then on 100 %. When I came home, four hours later, there was only 40 % power left. Is something wrong?