Thursday afternoon / night: tummy pains (as in lying on the floor crying because his tummy hurt)
Friday: pale and clearly 'poorly', slight fever, tummy pains and headache receded with nurofen. Went to GP, GP said viral or possibly the beginning of appendicitis but 'wait and see'
Friday (midnight): projectile vomiting followed by 'runny poos' and intermittent tummy pains - at one point he said his 'hip' hurt and pointed at lower left abdomen. Before and since he has always said that the pain is centered on his tummy button.
Saturday: tired but otherwise fine
Sunday: fine, eating as normal
Monday 2am: tummy pains, runny poos, intermittently throughout the rest of the night.
Now: pale but otherwise OK.
so, given that I am sleep-deprived and not thinking straight, I am leaving it to MN to decide if I should take him back to the GP or not.