Note that in the first exapmle there (from Griboyedov) it likely (I don't remember the context) refers to condition/mood of a character, while in modern speech I hear it...
Well, mood/feeling again, but the kind of it which can't be easily diagnosed by an observer:) And thus unlikely to appear in a such a categoric second person statement.
Vague feeling of disomfort, sometimes, not necessary, the one associated with literal reading: like in company not much familiar to you.
Or sometimes discomfort for an unknownt cause (of sosial, physical, nervous... any nature): целый день он чувствовал себя не в своей тарелке и не мог понять почему.
Note also possible etymology below