My macbook's little light doesn't went off but after 5 minutes it starts to blink, is it normal?

Why does my macbook pro when I put it in sleep it the little light doesn't went off - just on but after like 5 minutes it starts to blink like normal? Is it normal? One of my teacher said that my hard drive is going to damage and I am really afraid because I really love my macbook. Thanks so much!