MIL didn't want to give me my baby back

So yesterday we visited my MIL and my son was crying after a while because he was tired (usually he is only awake for 1 hr before getting tired and sleeping for 1-3 hrs). He has been awake for 3 hrs at this point because I told her he is tired and should be put down to sleep but she wouldn't put him down!! And when I went to take him, she left the room with him, and just held him while he was crying his head off! I was so angry! If my boy is crying, give him back to me! If I ask you to give me him back, then give him back!! 😬😠 I was soooo angry. I'm not overreacting am I? How would you feel?