Slowly becoming sister's slave

So i have a sister Cheryl, 18, who can be very bossy and demanding but its not something I've noticed before until she basically made me her slave without me even noticing she was doing it. About a month before she turned 18 our parents went away for a week for there 20th anniversary in the Caribbean. Now the thing you should know about me is that I'm very submissive so i'll do just about anything anyone tells me to and Cheryl took advantage of that in the week we had together. Since Cheryl was the oldest she was left in charge of the house ergo of me. They left us a grand to spend on food and drink and we had to compromise on what we would get but that wasn't the case so here we go; the week of how i became my sister's slave.