Classify the following sentence as expressing sadness, joy, anger, or fear.
I'm so overwhelmed.
The sentence "I'm so overwhelmed" expresses fear.
Complete the following task based on the instruction and optional input provided.### Instruction:
Classify the following sentence as expressing sadness, joy, anger, or fear.

### Input:
I'm so overwhelmed.

### Output:
The sentence "I'm so overwhelmed" expresses fear.