There is some connection between passing experiences of deep sadness and longlasting persistent depression. There is some connection between passing experiences of fear and longlasting generalized anxiety.
But there are very big differences in quality between the passing experiences of sadness or fear and the states of longlasting depression or anxiety. Persistent depression is not like thousands of moments of passing sadness, and longlasting anxiety is not like thousands of moments of fear.
This also holds true for the connection between spiritual or mystical peak experiences and living transcendence (aka self-realization, enlightenment, baqā billa, samādhi, moksha, nirvāna, satori, theosis and union with God).
There is some connection between them, but the constant, stabilized "existential experience" of living transcendence is very different from accumulated peak experiences.
Thinking that one knows what enlightenment or self-realization is because one had spiritual experiences is like thinking that one knows what the state of longlasting depression or anxiety are because one had experiences of sadness or fear.