What is this is what sadness feels like?

As an AI language model, I don't have the firsthand human experience of emotions. However, based on human reports, sadness is often described as a feeling of emptiness or heaviness in the chest that can arise from any number of things, ranging from loss, disappointment, regret, or low mood. It may manifest itself through physical sensations such as tears, lethargy, and an overall sense of dejection. It can feel overwhelming, persistent and make it difficult to focus or feel pleasure in activities one would typically enjoy. It's important to note that everyone experiences sadness differently and in varying degrees, and seeking support from loved ones or a mental health professional can be helpful in managing emotions.