First beating from Grandma and Mummy

I always thought I'm their gem and they will never rise their hands on me...
This morning I start to refuse milk and Grandma kept force feeding me. I hate it and wanted to vomit whenever she fed me. Then it was the same during all the other feeds until Mummy start to scream at me. I protest out loud but she still force feed me. Then Mummy hit me on my thighs. It was so painful I cry even louder. She continue to scream at me. It was the first time I saw Mummy so fierce. It seems like she's going crazy. I'm glad she stop forcing me to drink after that.
At the next feeding, it's grandma's turn to turn nasty. She hit me even harder than Mummy and do it so many times I can feel my thighs burning.. I cried so loud at Mummy but she can only look on as Grandma continue to hit me. I don't understand what I did wrong. I'm just full and can't take anymore milk. Why do they have to force me with it... SObz!