Scariest FTM moment, should I call the ER doc?

My daughter is 4 weeks old and never done this before.

This morning my mother was holding the baby up with her head on her shoulder, and she noticed she was kinda tense and not moving so she layed her down to look at her. Her face was PURPLE, not breathing, body tense and almost curled in a ball, hands in fists, eyes wide. She wasn't moving and was stiff. I was terrified and hurried and took her from my mom and began patting her back and blowing in her face. Idk how long while my mother was holding her that she wasnt breathing but after I took her and began blowing in her face it was about 30 seconds that she began shallowly breathing.

I tried to do research online but I cant find anything consistent with all her symptoms.

Anyone have any idea ?

My SIL almost died as an infant because she stopped breathing while napping and her aunt came in and found her unresponsive, luckily she was okay. I'm just afraid of SIDS or seizures....