Do I have worms? What does this sound like and should I see a doctor promptly?

Firstly, take some worm tablets just in case. This should destroy any in the gut if they are there. You dont need a Doctor to get these. Secondly a couple of days after the worm tablets - for the diarrhoea, take some pro biotic tablets (acidophulis, bifidis etc...) as this will greatly improve the diarrhoea as they get rid of bad bacteria in the gut, they work wonders. Headaches and diarrhoea are a clic example of bad bacteria in the gut. I highly recommend these tablets. You don't need a doctor for them either, you can get them at a chemist or health food store, they must be refrigerated too.