I can’t help you, but thought I’d bump up your thread so someone can. It would really help if you posted pictures.

Citrus trees in central Florida are almost 100% infected with HLB (citrus greening). See your county agent, if the tree is infected, and in your area it probably is, it needs to be removed quickly.

well, five years old. In ground? In container? Did you fertilize it? 50 fruits is a lot for such a young tree. My guess is too much fruit and not enough energy to grow them.