really beat up about this 😥

My aunts friend found a baby kitten that had been abandoned by her mother, and she left it with her son who is very hyper. Anyway his friend ended up sitting on her, and she was still alive when I offered to take her but she was very very lifeless. She only moved every 5 minutes or so, and she had no control over her body. Around 9 o'clock at night I got paranoid that she wasn't breathing so I took her to an animal rescue lady. She made it through the night but passed earlier today, and it didn't bother me earlier but it's really bothering me now. I can't stop crying. Maybe it's the pregnancy hormones but I keep feeling that maybe if I did something different she would have made it. Anyone wanna give me some advice? (The only vet we have with an emergency number was out of town, all other vet clinics were closed because it was Sunday)