I Have Felt Sick Since Yesterday Morning. My Stomach Is

I have felt sick since yesterday morning. My stomach is in serious pain and it feels like I am going to vomit. My stomach pain gets worse when I eat or move. I am a little dizzy and lightheaded also. And I'm tired all the time since yesterday morning. There are two possible things I think that might be causing this. I am wondering if both are wrong or one is right or something. I don't really know, I would just like an experts advice.