Many illnesses can cause nausea and vomiting. Some are mild and will pass by themselves, but others are serious and need medical attention. Try this decision support tool to help narrow down possible causes:
If your symptoms persist, see a doctor for further workup and evaluation.
Other things besides stomach ailments can cause nausea. Inner-ear ailments or stress can do it. Also, change of food (such as, someone moves to a different state and is bothered by the water or eating in the college cafeteria) can do it. I would also suggest you seeing a doctor.
Sorry to hear. This isn't like a stomach bug, is it? If not, one thing to think about is stress and anxiety. This can impact your gi system. My son has anxiety and stomach nausea is one of the things he mentions on a regular basis as part of it. I know you are under a lot of pressure in college so could that be involved? And ulcers. I had a duodenal ulcer which is one in your small intestines and it wasn't like what you think an ulcer would feel like. I didn't have pain, I had nausea and I had it a lot right after I ate. I ate less and less and lost 30 pounds. An endoscopy found it and once they saw it, the medicine took 2 days to work after 6 months of feeling horrible. But that is something to consider as well.