When Raina Telgemeier was nine years old, she woke up in the middle of the night with a terrible tummy ache. She had caught her little sister’s stomach bug and spent the night hunched over the toilet. Her flu passed quickly but her tummy troubles were only beginning. Soon she started getting stomach aches at least once a week—sometimes several times a day—and became terrified of throwing up and pooping her pants. “When I had a stomach ache, I would go into a panic spiral,” she says. “My heart would race, my head would pound, my palms would sweat, I would not be able to concentrate.”