Update, it is getting very hard to watch Krissy fainting. It is happening more often.
Today they did a complete blood serum and took x-rays from the top of her head to her stomach. Her blood pressure and trachea is fine. She has a fever and a enlarged heart and liver.
Looking at the x-ray broke my heart, she looks fat due to everything being enlarged. The three vets actually say her faint and were shocked, only one had seen it before and wouldn't say what was the cause because she didn't want to worry me.
Tomorrow she will have a EKG and them we will schedule an MRI.
Two things come to mind - Liver cancer or a brain tumor.
It doesn't look good so please keep her in your prayers!