Hyper sensitive to other's body movements

This happens to me occasionally: I will be in a group setting, and I will fixate on someone, often an attractive co-ed, and then when they move, to brush there hair from there face, or shift in their seat, etc, I notice it, and I feel compelled to move slightly as well, and I will involuntarily fidget, like a tic I guess. It is mild enough so people probably usually don't notice it, but it is very uncomfortable at times, as I feel hypersensitive to something which is a waste of my attention. Does anyone else experience anything like this?

Sometimes I will wonder if they are noticing it, and that makes it worse. Sometimes I wonder if everyone is uncomfortable with how I seem to be fixated on this one person, even though upon reflection I realize that this is unlikely due to how slight my responses are and how any awareness of them would constitute pretty much the same fixation that I have in the first place.