I have had kids that stressed me out and would make me cringe when I knew they were coming that day. It is normal not to like every one of them - although I try to see the good in every child.
I think it is amazing that you have had this much patience. You deserve an award.
Hitting you, peeing?Is the child developmentally challenged/delayed?
The food situation is stressful enough because having 1 kid say "i don't want that" or "I hate that" makes other kids also reluctant to eat what is there....but I think you have good reason to say you can't do it any more to the parents.
I guess the part that sucks is whether you give 2 weeks notice and whether you are then only saving yourself two weeks of sanity or can you terminate sooner?
I feel your pain - I really do