Bloating/ gas constant over last month. Diangosis gastroenteritis. Still uncomfortable. Could it be something more? Ibs? Celiac? Taking lots of simethicone

Many causes. Abdominal bloating can have many causes including ibs, celiac, small bowel bacterial overgrowth, c. Difficile or other pathogen, lactose intolerance, gallstones, ovarian cancer, pancreatic problems, an obstructive problem w/ the colon, inflammation anywhere in the abdomen or urinary tract leading to an ileus(slow down in the contractility of the colon), etc..Go back to ur doc for a more thorough evaluation.
IBS is possible. Acute gastroenteritis (age) does not last one month. We often see post infectious irritable bowel syndrome following age, which can last weeks-months. Post infectious ibs is best treated with dietary adjustments. I recommend the low fodmap diet for 5 weeks. Celiac is uikely, but lab testing for this is quick and easy and should be done.