My mom has Atrial Fibrillation of heart & congestive heart failure.

I just found out today that my Mother does not get enough lung function even with oxygen to cleanse out all the carbon dioxide....this makes her sick to her stomach and very tired. She also says she cannot catch her breath.

What has her cardiologist/geriatric specialist said? Has she had any new meds introduced recently? Is she able to eat something before taking meds?
I give my mother pure ginger candies when she complains of mild nausea. Ask her doctor if it is okay.
But this situation sounds like more than just the nausea. She could have an intestinal bug or something more serious.
Talk to her docs ASAP.

Good luck.