The easy part is to simply say the poor girl is seriously deficient. This is a clear problem. The reason why is another question however. Likely, it just needs to be fed. Go low but more frequently in feeding. When I suggest "low", higher than you are now, but not very high overall. No idea without more info. There is the likely possibility that some sort of pH lockout is going on. In other words, you are feeding her, but hte nutes aren't available... most likely because way too acidic in the medium. Not knowing what you are in, how often, ppm (in & out), etc, etc, etc, its tough to say. The answer is nonetheless the same. Feed with a light solution, properly pH'd, 3-4x the volume of the medium. THe plant should perk up almost immediately. However, with the massive K deficiency, don't expect the leaves to ever look normal again. New growth will be greatly improved. Best.