Hello & welcome, I am Dr. B, a licensed veterinarian and I would like to help you today. I do apologize that your question was not answered before. Different experts come online at various times; I just came online, read about your situation, and wanted to help.
Again I do apologize that my colleagues could not aid you sooner. If you would still like assistance, can you tell me:
Did the bloods show anything abnormal (ie elevated white cell levels)?
Do they eat when treated with the anti-nausea medication?
Any access to toxins, plants, chemicals, or anything similar?
Any changes in urination?
Are they fully vaccinated?
Have they been tested for feline viruses (ie FeLV, FIV, Coronavirus, etc)?