Sister Rant!!(long)

Okay so im 33 weeks pregnant and my sister needed a baby sitter for a couple of weeks shes gunna pay me ofcourse for watching 2 kids from 5 am to 630pm 4 days a week im getting 200 dollars every2 weeks i dont have a problem with that at all....the thing is i have to walk my nephew to school and pick him up which ofcourse isnt bad either i need the exersise but on top of asking me to do all this she asked me to spend the night those days that i have to watch them... I told her no i have my own home i have my hunny at home and even at that i have stayed with her and watched the kids and when she gets home from work she dosent give me a break she lets the kids stay with me while she sleeps or goes to the store and im only getting 200 dollars shes not gunna up it if i stay the night so i told her no and she got mad saying that i really hurt her feelings because she has to wake up the kids at 5 am to come get me and this and that but she did that with the last babysitter she droped them off at her house at 5 she had a car to take him to school and she never had a problem with ut then...like just coz im ur sister dosent mean i Have too stay the night and im just watching them till i have the baby but still for her to get mad at me for not wanting to leave my hunny alone at home for 4 days and only b there 3 days and only for 200 dollars that bullshit my mom has to go to work with her my mom can watch them while she comes and gets me i stay less then 10 mins away am i over reacting???