Sadness

sad·ness
/sadnəs/
noun

the condition or quality of being sad.
"a source of great sadness"
synonyms: unhappiness, sorrow, dejection, depression, misery, despondency, despair, desolation, wretchedness, gloom, gloominess, dolefulness, melancholy, mournfulness, woe, heartache, grief; informalthe blues

"our sadness cannot be measured"