Dislike for children

I don't know if this is the proper place to put this but I couldn't think of another room it would go in. I apologize if it's in the wrong place...

I nanny a 19 (at first, I put 16. However, I miscalculated.) month old right now. And he absolutely drives me nuts! I am also 37 weeks pregnant. Granted, he is ridiculously spoiled, throws tantrums, gets his way 99% of the time, never learned "no", etc. However, I can't bring myself to like him or be playful with him. I am kind to him and not abusive or cruel by ANY means. I am just generally annoyed by him. There is nothing cute about him to me and everytime he throws a tantrum and gets his way (via his brothers and sisters) I literally can't stand him as if he were an adult. And when he cries, I don't feel bad. At all. I'm not trying to sound like a terrible person...I am trying to be as honest as possible. Anyways, I am worried I will be like this with my soon to be son. I wonder if maybe it isn't because he is spoiled but maybe I'm just not good with children. I'm terrified I will have this same intolerance and be a bad mother.

Does anyone dislike other peoples children but have patience and compassion with their own?

Would you be the same way as me if the child you watched was spoiled? Or are "babies just being babies"?