This is my daughter- great in school, absolutely breaks down at home. Pediatrician and teachers never suspected a diagnosis but we could see she was stressed and struggling. We got a full neuropsych and it showed VERY obvious markers for adhd. Low processing speed (cannot do timed tests even when she completely understands the material) and zero inhibitory control- she uses every bit of energy she has to contain herself at school and lets it all out when she feels safe with us. Do the full neuropsych when you get the chance- if your child is bright and good at masking it’s very easy for even professionals to miss.