The Brave (But Scared) Child
What she's feeling: Not gonna cry, not gonna cry, not gonna cry. Not even gonna say goodbye because that'll make me cry. Just gonna knead this Play-Doh like crazy.
Your response: Don't panic if she doesn't say goodbye. She's just trying to hold it together. Say goodbye, but don't pressure her to respond. And don't talk about how you'll miss her or how sad you'll be without her -- it'll make her feel bad.
P.S. There's a chance she'll completely lose it when she sees you at the end of the day because she's been holding her feelings in. Make sure you spend some relaxing, calm bonding time together after school.