I can see you have two small LED bars on it, what is the rated watt draw down on those?, not the stated watts but actual consumption? A plant that size would need a minimum of 200w draw down and lights positioned over the top of the canopy to continue fruiting and photosynthesizing at a reasonable rate i reckon, also agreed with smokin, if its also transplant into a pot and is now starved of light the environmental stress will cause it to shut down and drop to preserve the stem and reshoot sites.