Why did my guinea pig die?

i filled her food the day before yesterday and noticed this morning she hadn't eaten very much and she was acting off so i took her out of the cage. her eyes were watery so i wiped it away and when i was petting her she didn't squeak or "purr" but i had to get to work so i put her back in her cage. i came home tonight and heard her bells going a little bit then it was quiet i went to go to bed and found her dead. it looked like she had been kicking and was in distress (possibly why her bells were going off) when i removed her from the cage it looked like there was stuff in her mouth, but im not sure what it was. her cage sits on the floor in front of my bedroom window next to my bed. it was 94 degrees out today and we had the air conditioning on, but i forgot to close the blinds in my room could that have caused her death? she was about a year and a half old and was perfectly fine for the past year and up to i would say yesterday into today. she had a respiratory disease previously that was treated with beytrol so im pretty sure it was not respiratory.