I Have Had Ongoing Diarrhea For About Two Weeks Now.

I have had ongoing diarrhea for about two weeks now. My son had the stomach flu: throwing up first and then he had diarrhea. I had extreme fatigue and then diarrhea. It doesn't seem to be going away very quickly. How worried do I need to be about this? Before my son was born I had a bout of stomach troubles like this. They have been gone for about 9 years now. I fear they are back. I have been eating less and more carefully, but I have not had many solid bowel movements in the last two weeks.