一、基础表达类

1. I'm sad.

2. I feel down.

3. I'm not in a good mood.

4. My heart is heavy.

5. I'm feeling blue.

二、情感延伸类

1. I'm having a bad day.

2. This pain is unbearable.

3. I'm lost and alone.

4. The world feels so empty.

三、文学化表达类

1. The best way to grieve is to forget, but the hardest part is never forgetting.

2. Time heals all wounds, but it never truly cures them.

3. I'm a ghost in my own life.

四、特定场景类

1. Lost in the memories of what could have been.

2. The silence is deafening.

3. I'm drowning in a sea of regrets.

建议根据具体场景选择表达，日常交流推荐使用基础类句子，文学创作或深度表达可参考延伸类和文学化句子。注意情感表达需结合语境适度使用，避免过度沉溺负面情绪。