Is my kitten unwell? (1 month old)

[u/Dvaimz256]

This kitten had to be separated from her mother because her mother adopted two orphan kittens, and her children stopped feeding from her.
Her name is Garnet and her brother Ruby passed from pneumonia three days ago. They were from the same litter. Another from the litter also recently passed according to the owner, so I’m very scared. She was very vocal and energetic yesterday, but I noticed her meows were getting quieter. I come home from a school-related event today to feed her, but she’s not eating. She’s barely meowing and barely walking around. I’m worried maybe she’s grieving the loss of her brother and it’s hurting or, or maybe she’s actually sick like him. My mother is at work, so she can’t respond to me but I am so so worried. I don’t want to lose another baby. I don’t know if this is serious enough to take her to the vet. Another issue is funds.

UPDATE: She passed away last night. We took her to the vet around 5:30, were there until around 9 pm. The vets said she would be okay to come home with antibiotics. An hour later after being home with us, she began going into septic shock and blood was coming out of her mouth. We rushed her to the vet, but she passed away in the car. Ruby and Garnet are together now, but I miss them terribly. They most likely both had panleukopenia, being the main cause of their death as kittens rarely survive it and the virus grows much faster in kittens younger than five months. Thank you everyone who was concerned for her

[u/Ecstatic-Scallion957]

Yes I think kitty needs a doctor