When this happened to me, my doc suggested it was irritable bowel, but affecting the stomach. I took mebeverine (?) (called Colofac in the UK, and purchased over the counter at the pharmacy)half an hour before each meal, 3 times a day for a few days. It cleared up the symptoms quite quickly! Make sure with your doc first thoough, and good luck.
It is very common. With all three of my pregnancies I just didn't feel right kinda like having a mild version of the flu. I would definetly wait and see if you miss your period and test. Try eating more starchy foods and drink some sprite. And if needed you can take TUMS or tagament and it wont harm the baby if you are pregnant. I am not saying you are but just in case.