In Plato's theory of forms, what we see is not the thing itself, it is simply a shadow. Perhaps emotions I can name are simply shadows of the real felt sense.
Try this exercise:
Get comfortable. Close your eyes and count backwards from 100, slowly. When you get to zero, try to remember your first kiss. Spend a few minutes with how you felt, but don't try to define it.
When you're ready to open your eyes, describe in words that felt sense. Don't be afraid to use simile and metaphor, even make up words.