How do you deal with all the uncertainty?

SO is currently undergoing IVF #1 and the protocol appears to literally change by the day. She had a sonogram today and the doc says he wants come in tomorrow to personally do another one. We have not idea why yet.

How do you deal with that kind of constant lack of knowing how things will turn out? Nothing else I do to distract myself seems to draw my attention away from the possibility of this cycle being terminated prematurely or worse news that renders IVFs not viable. It's driving me up the wall. What could be more important than this? How does one sustain themselves over months and years of not knowing?