Is there a way if i can tell if tummy pain diarrhoea and constapation is down to anxiety or an an actual problem when having flare ups?

Yes. Irritable Bowel: Syndrome, often associated with anxiety, is an "actual" problem. Seek evaluation by a gastroenterologist to differentiate a functional GI disorder from ones that cause changes in the GI tract itself, e.g., auto-immune disorder, inflammatory bowel disease, infectious process, diverticulosis, benign or malignant tumors. Diagnosis will guide treatment, even if it is "just" symptom management.