I've been struck down with a tummy bug for the last few days, grim isn't it :(
Have heard there's something going round so may be best to keep away from work until you're better in case you pass it on.
Is there any other reason for it than a tummy bug? You can get diarrhoea medicine like loperamide but if it's a bug or something then best get it out of your system.
Avoid anything too sweet as it may make it worse, drink plenty of fluids, preferably water and if you're getting dehydrated try the rehydration sachets. If you can't keep fluids down then get to see your GP.
See if you can stomach some gentle soup, just liquid at first then something with some soft veggies in then when you can tolerate that try some dry toast.
Hope you feel better soon! x