Think of it this way. If you were to think about a lemon and picture yourself cutting it in half and then taking one of the halves and squeezing it, if you did that, even if there isn't a lemon anywhere in sight, you would be able to smell lemon AND your mouth would start to water as tart things usually make us do. Our minds don't know the difference between real and imagined, so your saliva glands would have to be stimulated by your thoughts in order to cause the physical reaction of your mouth watering, correct? Otherwise where is the additional saliva in your mouth coming from when you think "juicy tart lemon"? Well, same thing with stimulating the vomit centre by focussing so much on not vomiting. Your brain doesn't get the "not" part, all it "hears" is "vomit" and because your brain is healthy and works perfectly well, it goes into action and stimulates your body to feel like it's going to vomit - ie nausea.
Yes it's really all gone. It's only been two weeks but I've been feeling consistently "normal" every day, no more nausea, no more chronic scary thoughts of "what if...", and no more obsessing about everything being contaminated and getting sick. I don't WANT to vomit and I still have an "ew" reaction to it if I see it, which is normal, but that panic-attack inducing terror that made me seriously consider killing myself to make it stop, is finally gone.