guinea pig is not pooping

Question
My guinea pig has stopped pooping,she had about 5 poops this morning.She is only 8 months old,she is not eating right now,and not active...help,I don't want to lose her.

Answer
She is certainly sick. You need to take her to a vet to get looked at asap as not eating and drinking is a sure that a guinea pig is sick. How long has she been acting like this? Have you been giving her vitamin C everyday?
The only thing you can really do is take her to vet and you need to hand feed her to get nourishment in her body. Here is a link on hand-feeding and exactly what to do.  
http://guinealynx.com/handfeeding.html