I read this book in my early teens and have been trying find it for years. A father sends a young girl away from rubber farm during the war. Upon her return from England, she finds she is an outsider due to not suffering the same pains those that stayed suffered. Her childhood friend (a boy) helped the villagers/prisoners by going night fishing to help keep people fed. The story resolves her relationship with the boy and her father.
sounds like All Our Yesterdays by Stuart Buchan.
http://www.publishersweekly.com/978-0-373-98006-2
This is it!!!! You are amazing.
Thank you so much