We made it. After a month of worry, doctor visits, tests (including yet another one of these), several priesthood blessings, and many tender mercies of the Lord, Phil is feeling better and is back to work.
I cannot begin to thank you for your thoughts and prayers. Those first two to three weeks were very hard on me emotionally, but although "weeping may endure for a night, ... joy cometh in the morning." The experience was hard, but I found peace in unexpected places. Because I know that others out there are struggling with their own challenges, I wanted to share the scriptures that helped me the most:
Thank you, friends, for your concern and your prayers. No one should ever have to go through something like this alone, and you became my rock, even though I may not have reached out directly to you for the support.