Are they consistently taking a path different than the usual upon noticing your presence? Do they evacuate the room (even if subtly) whenever you enter and make your presence known? Do they watch where you are going and shift their own course accordingly? (Watch the eyes) Do they come up with out-of-place or overused excuses in order to leave any conversation with yourself involved? Do they make a point of addressing other people in the room while ignoring you? If the above apply, there may or may not be people avoiding you. Congratulations! You have become socially ostracized!