Puppy lethargic and not eating

My 10 week old puppy is very lethargic and not eating. She's normally very lively and bouncy and as this is my first dog I'm not a very experienced dog owner and I'm really quite worried at the very sudden change in her. She hasn't vomited and is peeing and pooping okay, but won't eat.
We are taking her to the vet on Saturday as she is due her second set of shots.
Any advice would be greatly appreciated.

I would get her to the vets now

Go to vet now

Vets straight away, even more so as this is such a young pup!

I agree, get to the vet a.s.a.p. and I doubt he'll be having those 2nd shots until he's back to full health, coz they just won't do them, so it's a really good job you noticed he's off colour so you really must tell your vet! good luck with him, I hope it's something simple like he needs worming or something.

Please don't wait until Saturday, your pup needs to see a vet now!

Totally agree - vets now as puppies can go downhill so very fast, just like babies.

Yep, I agree with everyone vets now, hope she picks up.

Please don't wait. I don't want to alarm you (or perhaps I do) but Saturday may be too late....

Please get to your vet as quickly as you can - your puppy's life depends on it......

Good luck x

Echo all of the comments above. Puppies can go down hill rapidly so ring the vets as soon as possible