I decided to do just that - called the birth centre this morning and they advised me to go into emergency at Royal womens to see a doctor.

she confirmed that it was gastro and gave me intravenous fluids and advised a few days rest, to drink heaps ect.

baby is doing well though which is the main thing, so glad that it is something that will pass and not what I have to look forward to for next 6-8 weeks

So lesson learned, it is always good to get diarrhoea treated asap.