Our baby Hannah has a stomach flu now, too

Our baby Hannah caught up with us; our older daughter Tiana and me with having a stomach flu now, too. I was thinking that yesterday when all she did is sleep and didn't want to eat a lot. I gave her a bath then because I thought it would help her not get sick, but to my surprised early this morning she was making a sound like she is going to vomit. And when she finally got up, she vomitted-several times. So our little one has the stomach flu-if we indeed have the what people call it here a "stomach flu". What else could it be with our kind of symptoms? We never really had this in all the years we lived here, just this year. Perhaps the rapid changing weather is affecting us healthwise. I can't figure it out. What could be making us sick? It has got to be the weather. It's the culprit because when we go out in the cold we get a cold. And now that it is Spring. well, the atmosphere is changing quickly that maybe the fact that it is going from cold to warm, we get affected. It is like high tide and low tide, or full moon, pregnant women seems to give birth more than any other time. It's the full moon effect I hear. Is there fact in that? It is superstitious...sort of.