Eustress is the positive stress that you get from riding a roller coaster, or a high speed bike, or singing in front of an audience. You usually feel very good afterwards. Distress is the negative stress that you get from being arrested for drink driving, caught out by your principal, found out by your mom. You normally feel very bad afterwards. You often have the same bodily reactions (sweat, trembling, shivering etc) for both eustress and distress.