Well, kitten, you're not alone. We all have our ups and downs - and yes, for some, the roller coaster is far more tumultuous. But, generally speaking, it does get better. Darkness gives way to light, and soon we begin to purr again. Our metaphorical litter box is filled with clean gravel, and we realize that the next catnip bender, battle with invisible beasts, or stalking of the Evil Red Spot of Light is just around the corner.
Come to think of it, though, kitty, you only seem to be truly happy when you're pummeling someone else. So ... um. Your torment is relieved only when you can torment another?
This is why I'm a dog person.