Was It My Granny?

This incident happened about 6-7 years ago. I was in class 10th preparing for my board exams.

Now let me first give a brief introduction about my home and my room. My house is a 3 BHK flat. My study room also is the puja (prayer) room. Earlier when my granny used to stay with us, she used to sleep in my study room as a bed is also there. She died when I was in 8th std, that is 2 years before this incident occurred. The kitchen is visible from my study room.

Now back to the story. I was preparing for my 10th board exams and used to study until 1-2 am. That day I slept at 1 am and called out to my mom to wake me up at 6 am. She replied with an yes. I slept in that same room (the prayer room as it had the bed and my room was under construction).

At around 4 am it felt as if someone was waking me up my vigorously shaking me. I clearly felt someone's hand on my shoulder and trying to wake me up. I woke up to find that the time is 4am. I looked at the kitchen to see if my mom is awake as she wakes up quiet early. But the kitchen light was off. So I went to my parents' room and saw that both of them were asleep. Shrugging off this incident as my imagination I went off to sleep.

Again at 6 am I felt the same shaking feeling and I woke up with a start. I finally decided to ask my parents. It was shocking to know that neither of them had woken up to wake me up at 4 am or 6 am. And my mom declined even answering last night when I had asked her to wake me up as I was going to sleep.

I am still wondering who could it be who answered me and what was that I felt? Can anyone please help me understand...