Booked to stay over one night, client is asking me to come early Saturday morning, and leave Sunday night?

I feel like this is taking advantage of the "1 night" booking. Walking three times a day, giving medication, feeding twice a day. I'll end up getting about $21 gross for two days of work. She wants me to start at 9am Saturday, and stay at least until 2pm Sunday

Is this acceptable? What time limits should I put on overnight sitting?