Zucchini is Shriveling Up?

Sounds to me like maybe the fruit are just not forming due to lack of pollination. If the female flower is not pollinated, the fruit has no reason to exist, so it just shrivels up and drops off.

We usually pollinate our zucchinis by hand. Whenever we have male and female flowers at the same time, we pluck the male flower off along with most of the flower stem. We then peel away the petals of the male flower and "brush" the pollen (borne on the anthers of the flower) onto the female flower's external "reproductive parts" (the stigma).

Early morning is the best time to do this, as the flowers tend to close up as the day
goes on.

Even though we have plenty of bees and other pollinators in our yard, we don't count on them to pollinate our squash. I hope you really don't have squash bugs--there's almost nothing you can do once they come along and
take hold.Try again next month maybe they will make better. Good luck.