I did this too in 7th grade, I was looking in the book again and I'm not sure what version of the book you have, but mine is with the weird cut pages and in page 33 I saw the line "why did he look sick now?" addressing Dally, and I read the whole page and it said they found Johnny beat up really badly. And it also says Ponyboy was confused why he looked sick since Dally had seen people beat up badly, but making an inference it must be since he knows Johnny and is closer to him, so he must've been beat up really bad.
The paragraph specifically talks about how the body responds to stress.It does not give information on the caveman,neither does it give information on how modern and ancient stresses differ.
You can that aunt marry is someone who is very nervous and cautious by how the author used the word shrieked and how you can infer she was scared by the tone of the story