Behind Me [Makmum]

Nurul is a diligent and religious student. One night, she wake up at 2 AM and pray as usual. She felt there is someone behind her and copy her movement during praying. She thinks that someone behind her is one of her friend. At last, she realize that she's the only one who stay at the dorm. Because all of her friends have gone back to their hometown. So, who's behind her?