Lethargic Kitten- When to worry?

 I recently adopted a kitten, Lizzie, from a family who found a litter abandoned. They thought she was about 6 weeks old but Lizzie is very small so I'm thinking 4-6 weeks. They had started her on kitten food.

I brought her home on Monday feeding her kitten food mixed with KRM and she quickly caught on to the litter box. On Tuesday, I noticed she was going a lot and the stools were loose. On Wednesday she was starting to go even more so I took her to the vet. She weighed in at 13.75 oz. They gave her fluids and worm treatment and said to call the next day if she was worse.

On Thursday she was having more yellow, mucus stools that became diarrhea. I took a stool sample to the vet who gave her an RX for Metronidazole (and it has to be dissolved and given by syringe as the smallest doses too strong for her size). She had her first dose Thursday afternoon and she spent the night very sick. (diarrhea and vomiting). She dropped down to 11.75 oz. I stayed up all night giving her Pedialyte and a tiny bit of Karo syrup (thanks for this site) when she started fading. 

This morning she was back at the vet for more fluids and an vitamin B shot. Since she has been home she has had a tiny bit of KRM and water and the tiniest bit of boiled chicken. I'm watching her weight (she is back to her Weds weight). She still had some diarrhea but not as frequent but she has been very lethargic and wanting to be left alone. She is sitting and just staring most of the time. No more purring. Just sort of there. I am not sure if she is just exhausted or if I should be worried. Advice?


 

Is the vet telling you this will be normal for a few days?

The vet didn't say. The vitamin B shot had perked her up as had the fluids (she was very dehydrated even with me giving her fluid all night long) and at the time I was more focused on what to feed her if she continued to avoid food and water. I had assumed she would continue to act active once she got home but that hasn't been the case.

I  also found out one of her litter mates passed away today so I am just worried about keeping her healthy. If her weight is ok and she is not dehydrated is there still a reason to be concerned?

She needs to start eating on her own. Is she eating? When the kittens are very young they aren't very very active. If she's closer to 4 weeks old she may not have perked up much just due to age. Have you tried just feeding the formula with no kitten food mixed in?

Yes and she vomited it up... I am not sure how much of a break she need between throwing up and trying again. I keep giving fluids. I will also take her back in tomorrow if her weight keeps dropping.

Can you snap a photo to see how young she is?

This one shows how small she is.

This one is from Tuesday morning.

She finally ate some AD cat food mixed with KMR (and warmed) at 4am. She had about 5 ml on her own. She still has diarrhea but doesn't seem dehydrated. She perked up for about 30 mins but after her medication is lethargic and back to refusing food and water.

shes still pretty young and if her mamma was around would still be drinking milk. I think in another 2 weeks you can expect a lot of activity. I wouldn't expect her to look like she is eating much. did the vet recommend you mix adult food in with the formula?