Yep - I've had gastro while breastfeeding and pregnant at the same time, and it sucked. I got really dehydrated and had to go to hossy, so make sure you keep up your fluids!!!!
Feed as often as bubs wants it as there is a chance they can get sick too from the bugs floating around, and your milk is the best thing for them.

Keep a bucket handy during feeding time in case you need to spew