I am sorry. I mis-read your question! I read it as "nine days after whelping" not before.
She does need to see the vet in my opinion.
Yes do get her to the vet today. Don't wait. It might be nothing more than an upset tummy. But right now she will be needing as much nutrition and fluids as she can get. Also her pups' survival depends on her! It could also be mastitis....have you checked her teats for any soreness, swelling or redness, and is she still producing milk out of each teat?
Her temperature will need to be taken. But you can wait to let the vet do that if you prefer. As knowing if she has a fever could help with diagnosis. Even if you found she did have a fever she would still need to see the vet.
I hope she is better soon.