I would suggest that you go see your primary care doctor
about this. Any set of symptoms like this that go on for more than one or two weeks should be checked out.
The most likely problem that you could have is an imbalance in the amount of acid in the stomach. This can cause nausea in several ways. First, acid may wash out of your stomach when you lie down into your mouth and esophagus. This is called acid reflux
, and it can lead to a sour taste in the mouth and nausea. Secondly, you may have gastritis; this occurs when the stomach acid irritates the lining of the stomach, leading to nausea or pain. Finally, you may have a stomach ulcer; this occurs when gastritis goes on for a while and leads to breakdown of the stomach lining. It is important to have this diagnosed, because if inflammation of the stomach goes on for too long it can lead to bleeding
and other problems.
There are several medicines that are used to decrease acid production in the stomach, and your doctor can help you pick one. Additionally you should avoid things that are irritating to the stomach, especially caffeine, alcohol, and smoking. Again, please discuss further with your primary care doctor.