Rowling was divorced and worked on the book part time while teaching English. She applied for a grant to the Scottish Arts Council to give her time to finish the first Harry Potter book, and used the grant to write full time until the book was finished. While waiting for the book to be purchased by a publisher, she returned to teaching English. Rowling is multi-lingual, and also taught French. She didn't give up teaching until Scholastic bought the US rights to the first Harry Potter book, which provided her with enough money to write full time.
She was hardly a welfare queen.