Any advice please..

Yesterday i woke up, was sick (nothing new there) but then had to run to the loo regularly all morning, risked popping out to do some stuff and started getting stomach cramps so bad they had me in tears in the car park... DH left work got a cab to where i was and drove me home, lots more trips to toilet, went to bed for the arvo still getting cramps but not so bad.
Still got the diarrhoea this morning.. DD1 mentioned runny poo when asked but had not complained about it DH and DD2 seem fine. So I'm assuming its some sort of bug.

Is there anything i can do to help? eat or not eat?

I just feel so weak and sorry for myself. DH could not stay home, so i'm here with the girls (dont want to send DD1 to school to pass it on) Ugh.. I have so much to do, but its a movie day i think.