How awful you poor thing I think you can take Hydrolyte or Gastrolyte for hydration but best check witch one is ok with the pharmacist.

I don't know if it is safe to take Immodium or the like for the diarrhea again check with the chemist.

I had bad M/S and was given Maxolon for the vomiting but you'll need a script for that from the doc and if the gastro is going to run it's course in 24 - 48 hrs it might be best not to take it and just hold out as horrible as it is!

But definitely keep your self hydrated!!!

Hope you feel better really soon!!!