m/s can do anything. I have had m/s that has been for a very short time and then just disapeared. I have had m/s that comes and goes for the whole pg, and this time I have had very servere m/s which has now eased off and just remains as a mild nausea. If your m/s disappears try not to worry, it probably doesn't mean anything except that you are lucky enough to have it go.