Enlarged mesenteric lymph nodes are often a normal, protective response to mild inflammation or infection in the gut, explaining your slightly elevated ESR. Since this has persisted for six months, treatment focuses on addressing the underlying cause. For immediate symptom relief, a doctor may suggest generic antispasmodics (such as dicyclomine or mebeverine) for pain, and simethicone to reduce flatulence. Probiotics may also help regulate your digestion. Please do not worry, as reactive lymph nodes are very common and typically benign. I highly recommend consulting a gastroenterologist for a comprehensive evaluation to determine the exact cause and receive a targeted treatment plan.