Miriam...I've been testing for two solid days and missed most of this thread until just now.
Keep getting tested until the doctors figure it out. This is an issue that you need to resolve, but medicine isn't a straight line. Figuring it out is the important thing--what it costs, it costs.
I know that sounds cavalier, but since as I type I owe Sloan Kettering approximately a year's net pay, I can say it from the heart--whatever the price of figuring out a critical medical problem, it's preferable to the alternative.
Positive energy from central NY is heading your way...