constipated

My baby hasn't pooped for five days, and today she's not wanting to eat. She usually breastfeeds and formula feeds. She won't take any formula she'll only take breastfeeding but I don't know if I'm leaking enough milk so i can't tell if she's getting enough. I don't want her to get dehydrated. Yesterday I changed her diaper and it only had a poop stain like she tried to go. Should I see a doctor today about her symptoms