desperate for advise- how to tell someone...

Abigail
Help me please! 
I live with my boyfriend and I've been living with him for a while, we actually just moved and MY name is on the apartment lease along with his and a room mate, which my parents don't know. (my parents love my BF) 
Im 20 years old, have quit school for the semester/year (bad grades, don't know what I want to study, etc) and I'm 2,000 miles away from where my parents live. 
I support myself, I don't borrow money from parents or bf. 
Me and bf went home to my family for Christmas, and I left a couple days after bf. On the way to the airport at 4 in the morning, my dad said that my plans have been a failure and it's time for them to make choices for me. He said I need to move back in with them (which btw is a state that I have never lived in) and go to community college there starting in like 2 weeks.... and work for him at his company. 
My parents paid for my college while I got bad grades, my parents love me and I love them... I'm the oldest of 4 children and they are so overprotective they give me no freedom yet expect the world. 
When I talked to my dad I tried to remain nuetral like 'I will think about it' and 'i will check out the college' all while explaining MY plan and telling him how happy I am where I live now. 
It's been a few days now and it's clear they think I'm moving back in with them. What the heck do I say? How do I even start this conversation? I don't need to move back home with my parents... how can I be sensitive? My mother has empty nest syndrome as the next sibling is preparing to leave for college next year also... HELP