"Last night" has no bearing on today. If you feel OK then go to school.
If I vomit the night before, should I still go to school the next day?
It depends. Often times when someone throws up they feel better soon after. Other times like with the flu you can feel sick for days. If you are feeling better and not running a fever, I would say go.
Go to school.
What caused the vomiting? Were you watching a reality TV show?
If you feel ok and don't have a temperature or headache or anything then you can still go.
No . Its better you stay home incase your sick.