I Have An Extended Stomach And I Seem To Be

I have an extended stomach and I seem to be losing a lot of weight. I have a very small bowel movement, usually daily but some days not at all. I think I am losing weight because I don't feel like eating much. what can cause this and should I be eating more? I went to the Dr but he is a sports medicine Dr and I don't put much faith in him. He sent me to a Gastro Dr but I can't get in until September 30..should I be worried?