May be a reaction to vaccinations if you have had those recently. Can also be a reaction to flea medications if she has been exposed to those. She may also have gotten into something in your home that was toxic to her. I have seen some animals still continue to eat even though they are very sick. See your vet.
I would call the vet she is young and can get dehydrated fast it only takes less then 24 hr for young puppy to get dehydrated,The runny eyes could be allergies or in grown eye lash or somthing in her eye or and infection call the vet and see what he might suggest you may need to do a eye was or give her benadryl but she young so pls call the before you try anything.also you need her to start drinking you said she eating try putting water in her dry food or put sodium free chicken broth in her water 1-2 tbs. if she has not had anything to drink in 24hr or shows signs of dehydration then give her some pedialyte of kids but she does need a vet check soon