The phrase "am ashamed" can be replaced with a variety of synonyms, each with their own subtle differences in meaning. Some examples include "feel guilty," "regretful," "remorseful," "chagrined," and "humiliated." "Feel guilty" implies a sense of responsibility or wrongdoing, whereas "regretful" suggests a desire to change the past. "Remorseful" indicates a deep sense of regret for one's actions, while "chagrined" conveys a mild humiliation or disappointment. Lastly, "humiliated" suggests extreme shame or embarrassment. Using these synonyms can help add nuance and depth to one's writing by capturing the specific emotions and sentiments that accompany the feeling of shame.