I threw up my dinner from the previous night this morning. I have since developed a slight fever currently at 99.9, at it's highest 101. What's up?

Maybe food poisoning. Although vomiting and fever can be caused by food poisoning, it is still possible that you have caught a viral illness. On the other hand, if you begin to have sharp abdominal pain, if the vomiting continues and you become dehydrated, if you experience bloody diarrhea or high fever, see a doctor as these are all symptoms of a serious infection that should be evaluated and treated medically.
I don't know, but... With fever and vomiting...You should see a doctor...
Food poisoning. You might have eaten something bad, or contaminated with an infection - usually unintentional. Usually it resolves in a day but if your symptoms increase or worsen, see a doctor.