I hope she is ok. It may just be an upper respiratory infection, (URI). If a cat cannot smell, it will not eat or drink.
You may be able to provide some temporary relief by putting her in a bathroom and getting it all steamy, or allowing her to sniff Vick's Vap-O-Rub. This will not cure her breathing problems, but may make her feel better until you can get her to the vet.
We have some resident experts that may be able to give you more advice on making her comfortable, the above suggestions are what has worked for me and my cats, as well as some other suggestions that I cannot seem to remember right now, (senior moment
Please keep us posted on how she is doing.