whats your humidity and temps in the room? a high humidity near the end can lead to budrot that starts in the middle of the bud. by the time you see it, its too late. the bud will start to turn to mush inside.
last year i had to chop a week early when i caught it just starting to happen.
just because the buds are drooping doesnt mean something is wrong. they could just be fattening up and need to be supported.