The battery of my Droid RAZR, a few months old, is suddenly running out alarmingly fast - in about 8 hours instead of 48. I don't have many apps and close out everything I do use, regularly (included are phone calls, texts, a few internet sites here and there.) I don't surf, rarely check email, or hang out in social networks. I do plug it in when the life is under 40% and leave it charging overnight a lot. Could this be the problem? I asked the sales person at the Verizon store if it was ok and she said it was, although it should fully charge in one hour or so. What's wrong?