Keeping our kitten alive

Hey, it means the world that you’ve found this and are reading this. We bought a British Shorthair kitten for £1000 around 3 months ago, with the hope that if she was cared for immensely, then she might not get ill. My two children have been saving up for so many years and have wanted a pet for so long and it hurts me that she might have to be taken away from them. Daisy has had an extremely high temperature for the past few days and a heart rate that isn’t normal. We took her to the vets and they gave her two injections (one anti-inflammatory and another antibiotic) they also prescribed her dehydration liquids. for all this we paid £100. the vets wanted to keep her and do all the necessary tests on her to see what exactly was bothering her as she hasn’t done a poo for two days or eaten barely as much as she usually does but we can’t afford the expensive tests. If we can pay for those then we will be able to see what is bothering her. she is very withdrawn and sleeps all day and we are extremely worried about her. the vets today gave her laxatives but they haven’t helped either so we’re not sure what’s going on. it would help us so very much if you even shared this to other people as Daisy is our biggest joy in the world and we love her with all our hearts.