Sometimes I'm a Bombaloo by Rachel Vail, illustrated by Yumi Heo

From chapters.ca:
Sometimes, Katie loses her temper. Sometimes she uses her feet and her fists instead of words. When Katie is this mad, she's just not herself. Sometimes, she's bombaloo. Being bombaloo is scary. But a little time- out and a lot of love calm bombaloo down and help Katie feel like Katie again!