Ehnh?

Sara and I were talking tonight and I realized/wondered about how you would spell a "word" that isn't actually a word, it's more of a sound or a feeling...one that would best be described through a picture:

Did you guess the word/sound/feeling?  The best I could come up with is "ehnh" it would possibly include a question mark at the end.  Let me put it in context: "How do you tell someone that you like them enough to talk to them, but you don't ever see yourself making out with them? You know, it's kinda like 'ehnh, sorry, I just don't feel that way'."

I would include some synonyms for you, but that also has quite a few spelling problems/conundrums.