Going out and having a normal day will usually make you sicker. It also exposes those around you to illness. Stay home and take care of yourself so that you can go out again soon. Keep in mind that you're usually at your most contagious at the beginning of an illness — for a cold, this means the first three days, possibly four or five. Sleeping can be one of the most vital steps in allowing your body to get better. When a sickness attacks your body, it needs as much energy as it can to fight it off. Sleep helps give you that energy. Even if you do it every day and find it gives you increased energy, working out hard when you're sick doesn't give you that energy. It typically makes you even more drained than before and can exacerbate breathing or congestion issues. This will help prevent you from getting more germs and conceivably getting sicker. It's also going to help you get rid of the germs that have collected on your hands. Wash your hands with hot water, scrubbing with soap for at least 20 seconds.

TL;DR in Vietnamese:
Ở nhà và xin nghỉ làm hoặc nghỉ học. Cố gắng ngủ nhiều nhất có thể. Hạn chế luyện tập hay vận động mạnh. Rửa tay thường xuyên.