Reee Oh! :-) If they said "we're all. . ." and you are part of the group, you were supposed to say, "Great! What time?" or, "Awwww, I can't come, I've got maths to study for for a quiz on Tuesday" or something. If you "think" you are part of a group (or even just wish you were part of a group) you have to "act" like a group member and respond as if you ARE part of that group. Why would they have mentioned it at all to you if they didn't feel you were part of the group/didn't think you might be interested? They're not cruel; there wasn't an implied, "and you aren't invited, ha ha. . ." at the end of the statement :-) They were just "checking in" with another member of the group (you) who wasn't there in the original plan stage to see what you were doing/up to and if you could come along.