Sunshine Blue BB lost most of the blooms

Left: Mid March
Right: Yesterday

Most shriveled and fell of like this:

Fertilized mildly twice in the last two months. What went wrong?

Something similar happened before to mine,from a lack of water.The cause for yours may be different.

Yeah, that may have been it. Its in 5-1-1 mix with not good mulching at the top and there were some hot days in April here. I usually notice young growth drooping when there is lack of water, in summer, but I did not see that in the past month, so assumed my watering is enough. I may have underestimated the water needs during fruiting.