I have had an upset stomach for four weeks now, going from diarrhoea to constipation and back with some bad lower stomach pain, I ve been to doctors and generally given tablets to alleviate either condition, however, although my stomach is settling a bit all during this time I feel weak and flu like quite dizzy with no real energy. I am very fit and eat well,51 female and would like to see my energy restored, any advice appreciated, many thanks