For the flu I swear by this homeopathic product, it is seriously a miracle "pill" though not a pill at all. It used to only be available at nature food stores and the such but now you can get it pretty much anywhere.
It's all natural, you take it at the first signs of the flu and it (almost immediately) knocks out all of the symptoms of the flu and you are basically just left with a cold that you can deal with.
It's http://www.oscillo.com/

Good luck, hope you recover and enjoy your trip