Should I be very worried?

My daughter is only 2 1/2 months old and yesterday she projectile vomited a couple times, we mentioned it to the pediatrician yesterday (her two month check up was delayed a couple weeks) and he said as long as it wasn't colored and there wasn't anything wrong with her poop then she should be alright. Well she's hardly eaten anything yesterday or today and she just puked again and completely soaked her outfit. Her diapers aren't nearly as wet as usual... I'm getting worried about her getting dehydrated. She also has a slight fever now. I'm calling the pediatrician again when they open in a little bit, just looking for some words from maybe someone else who's had their baby get sick like this.