I Woke Up This Morning Fairly Nausous And Feeling Like

I woke up this morning fairly nausous and feeling like I might vomit, but I haven't. I ate a cup of yogurt and 3 tums and went to my meeting. Afterwards, I went and had lunch, thinking I might feel better. But now I'm feeling even worse. I've had mild diarreah today and have been burping a lot since lunch. I have a headache and feel a bit dizzy. When I press my abdomen, I have pain in the lower center and right, although I'm not sure I would say that it is sharp.
Flu? Appendicitis? Worth getting it checked out?