Take this situation; Everyone was given ice cream at the birthday party, except for Todd. After Todd got home, he felt very disheartened that he never got the chance to taste the ice-cream there. He really desired it and now it left a hole in his heart.
Think of it as feeling you get after a "missed opportunity" or "missed chance". You can never have it again in your life. Now the mark this situation would give a person, is there a word for it?
I'm guessing "yearning", "longing" and "hankering" would win here (perhaps I'm actually looking for them?) Or is there a more specific word regarding that situation or feeling?