Overwhelming anxiety from dx

Sex/neuter status: male, neutered Age: 13.5 Breed: orange History: recently diagnosed with hyperthyroidism (medicated and well managed), pancreatitis (medicated (felimazole 2.5) and dealt with), recent diagnosis of renal disease unmasked by hyperthyroidism - have an ultrasound for his heart coming up in 3 weeks because they think the walls are thickened and he might need medicine

So from the history alone it's a lot. This has all come to light in the past month and I feel I haven't had a chance to catch my breath or process or get used to anything, and atm it's eating me alive.

Right now and for the past few days his appetite has gone down quite a bit. I've read that it can be a side effect of the medicine he's on for his thyroid and I suspect that it's the cause. I had a prescription for an appetite stimulant but it's literally impossible to get atm, I spent 1 hour phoning all the pharmacies and the vet clinic to find a solution and eventually the vet clinic prescribed some anti nausea meds to help, but I have a feeling pausing his thyroid meds could help, but I also don't want to chance it.

It's been one curveball after the other, and I fear my for my cat's wellbeing and health. I'm constantly worried and anxious and I can barely function at work. My vet is great but she just loads off all this information, like when she called yesterday to give me the dx on the renal disease. Another curveball, and I try to rationalise that at least it can probably be managed through diet and we have a plan with the vet to send some urine samples etc but it's like my brain can't process the logic and concrete proof. Instead it's just "aaaaa!!! Worry panic worry!!"

So I wanted to ask, with his lowered appetite, if I should be trying to pause his meds, or take him to the vet to see what they can do (more costs and stressful for the cat)? I'm going to call them regardless, but I just need to ground myself and I'm hoping for maybe some uplifting feedback/advice on how to manage and what to expect from treatments now and in the future?