I think my doggies have stomach flu... help?!?

My little chihuahua started having loose poops about two days ago and in the last 24hrs its become increasingly bad! We changed his diet to scrambled egg and cooked riced to help settle the diarrhoea but its literally coming straight out, Not helping at all. I'm so worried as to why this has come on and how to ease it as his bum has become red and very irritated. My puppy has just started to get diarrhoea too so I'm guessing she's caught it now, I'm worried that it could be worse than it seems but its just mainly because my babies have never been ill (i'm taking them to the vet tomorrow morning, but just want to see if anyone has had the same experience)

Parvo season - ongoing diarrhea is an automatic good reason for a vet visit. Small breed dogs dehydrate alarmingly fast - make sure they're drinking plenty, get some pedialyte and 50-50 it with water. And get them seen as soon as possible.Parvo isn't nearly the death sentence it used to be - as long as it's caught and supportive care is started quickly.If it's something else, similar symptoms mean a lot of the supportive care will be similar - preventing dehydration, preventing excessive vomiting, and antibiotics to avoid secondary infections.You already have an appointment, so just keep them warm and comfy and keep the fluids in them until then.Oh and rice boiled with chicken broth, cottage cheese, and probiotic yogurt are also helpful for the runs.