I've been bloated for about 3 weeks. anything i eat makes my stomach look huge and i'm really skinny. also lots of gas too. what is it? im 19

Cut out all dairy: The most common reason for these symptoms is lactose and/or fructose intolerance. I advise you cut these foods out completely for at least 4 weeks. If symptoms don't improve you may need further evaluation including a lactose hydrogen test and stool studies that includes testing for certain parasites like giardia or cryptosporidium.