Your symptoms may be indicative of a few possible things. It is possible to have inflammation of the stomach only, without the intestines. This usually will present as nausea and abdominal pain but no diarrhea.
Ulcers can also present this way. There is a bacteria called H. pylori that can cause gastritis and ulcers. If this bacteria is present it needs to be treated to help the pain resolve.
This may also be a presentation of an inflammatory bowel disease called Crohn's disease. This would typically present with diarrhea but can present without it.
All this adds up to you needing to see your doctor for further evaluation. It also sounds like you may be getting a bit dehydrated, which will make your nausea and ill feelings worse. You may need a little IV fluid to help.