THESAURUS
conscience stricken
ashamed, conscience-smitten, full of remorse, regretful, remorseful, repining, rueful, self-accusing, self-condemning, self-convicting, self-debasing, self-flagellating, self-humiliating, self-punishing, self-reproaching, shamefaced, shamefast, shameful, sorry, unhappy about, wistful