What should I do for my 10 mth old baby? I think she has a stomache virus.?

My 10 mth old baby has just started puking everywhere. She has puked 3 times in an hour and a half. I offered her some pedialyte and she drank it but a few minutes later it came back up. Just wondering what I can do to make her more comfortable. Also how fast could she become dehydrated. What are the signs? Thanks.