This is sort of an inverse of this other question.
To explain what I am looking for, I had this experience when I was a teenager that a much older friend (who wanted me to feel as part of a group of people my age) took me to a party with quite a few other teenagers.
People at the party seemed nice and friendly but after being there just a minute or so I got an uncomfortable feeling and wanted to leave. It could be that this feeling surfaced when that friend told me that he was going to leave me and pick me up later.
He was not very happy about me wanting to leave as well but at that time I was not able to articulate to him how I felt. Also because I had not felt that feeling in earlier situations (likely because I had not had much social interaction in groups like that before) that feeling just seemed weird to me.
Many years later when I was pondering on that memory and realized that the uncomfortable feeling I had was simply a feeling of being intimidated (most likely about the social situation). I did also realize that this probably could have been minimized by some preparation (he had not told me in advance that there was this party going on where he wanted to drop me off).
Anyway, my question is about this aspect of feeling something but not being able to articulate what it was. Is there a formal name for this phenomenon in psychology?