Hello, my name is***** and I have over 20 years of experience as a veterinarian. I am sorry to hear that Francis has deep, labored abdominal breathing, vocalization and is laying on her side for the past few hours.
A normal cat has a resting respiratory rate of about 10 to 15 breaths per minute, and one breath is considered the in and out motion of his chest. If she has a rate faster then 50 breaths per minute at rest then she is in real trouble.
I generally guide owners by saying if you can notice that she is breathing abnormally then I am concerned for her.
Her vocalizations indicate panic and distress.
If she doesn't have a nasal discharge and isn't sneezing
then her difficulty breathing is likely related to a problem in her chest or secondary to anemia (decreased numbers of red blood cells).
Problems in her chest leading to an increased respiratory include primary heart disease (including cardiomyopathy and heartworm
), lung disease including asthma, bacterial, viral, parasitic (lungworm) or fungal infections, a mass(es) in the chest including lymphoma, heart based tumors or carcinomas, or fluid around the lungs (pleural effusion) due to a mass, bleeding, chylothorax or an infection.
Anemia can be secondary to poor red blood cell production, either due to kidney
disease as the kidneys make a hormone to stimulate production or primary bone marrow disease, or anemia can be due to bleeding or destruction of red cells due to a tumor, blood parasite or autoimmune disease (body attacks its own red blood cells and destroys them).
If your girl's tongue and gum color are a nice bubblegum pink them she is in better shape then if her gum and tongue color is blue or gray, these would signify she is real trouble and this is a true emergency.
The conditions I listed above are serious and I would highly recommend that your girl see a veterinarian promptly to have an examination and further testing done based upon her examination.
Francis likely needs radiographs of her chest to evaluate her heart and lungs to start and then further diagnostics based upon those findings. That may include testing for heartworm and lungworms, aspirating fluid for examination if there is fluid present around her lungs, or blood titers for fungal infections. In the meantime supportive treatment like oxygen can help her be more comfortable.
In the meantime keep her quiet so she can breathe as easily as possible.
Please let me know if you have any further questions.