Please take her to the vet. It is not normal @ all, so the sooner you
get her seen, the sooner it will stop. It could be any number of
things, but I am not qualified to tell you what it is, where a vet is,
& he can see her too, to evaluate exactly what the problem is.

I would imagine that she has a very sore bottom which is what is
causing her to cry. Kittens naturally learn from thier mother how to
use the cat litter, so my guess is that kitty is associating the pain
of going & leaking with her cat- Litter. if this is the case, you can
understand why she is avoiding it, where she would normally use it
properly.
I wish you well, & good luck @ the vets too.
Sheelagh