On the one hand, I can say that I sometimes feel a little lightheaded after a set of deadlifts too. However, it never turns to nausea, and no ear-popping either.
Perhaps you could try lowering your weight? I think if you lower the weight and still have the problem, you can start to look at your form. Are you holding your breath throughout? During a set of 8, you need to find a good breathing pattern.
Of course, actually puking after lifting super heavy (often after squatting) is a known thing, and whie it isn't a good thing, it's nothing to be scared of.
So chalk it up to intensity, pace your breathing or change reps range. Maybe fewer reps in a row will let you breath better.