Why is my poo yellow?

Hi for the last 5 weeks i've had diarrhoea especially in the morning, this morning however it was yellow! I've not got any pain just the diarrhoea, anyone got any ideas as to what it can be? I have not been eating anything different. Quite worried as my mum died last year with cancer of the pancreas and for a year before she had bad diarrhoea but they couldn't find anything wrong