I Have Just Returned From Sri Lanka After A 10'day

I have just returned from Sri Lanka after a 10'day holiday where we at a lot of seafood, drank water with ice cubes and since I came home I have found firstly that my stools were much lighter in color then I developed stomach cramps and bad watery diahorrea general weakness, tiredness and loss of appetite. As the journey was over 34 hours from where I live and I am 75 years old I am a bit concerned.