mmm, but at the same time...nausea can give you headaches... Vicki
The whole "she is sick so she must be pregnant" trope has never been depicted in these stories with the protag having a brain splitting headache. Also, she wouldn't just say she had a headache but also that she was nauseous. At no point does she think about nausea in the story. So no.
I'm sorry but can I just comment how pretty our boi chiwoo is