I'm in desperate need of help

I'll try to make this as short as possible but I'm desperate for answers.

I live at home with my parents, a 20 year old college student. I used to live on campus but they made me move back because they claimed we didn't have money, but I now realize it was so they could enforce rules and have even more control over me. I don't have a life, they make sure of that and you can call me petty or childish but let me explain.

I had plans to go out for one day this week but that was cancelled because my mom decided to bring it up with my dad out of spite. My dad then proceeded to say that I'm not allowed to go anywhere except school and back every day, that I have no reason trying to be doing stuff for myself or hanging out, that I'm being slick for saying it, then he threatened to take my car. I've told them multiple times that I'm trying to do things by myself so I won't be stuck home bored every day. I have done nothing wrong but yet they're growing tired of me, and they've made it known several times. "if you keep up this behavior..." this has been going on for YEARS and I'm finally trying to leave. It may not seem like much but I haven't gone into much detail. They don't let me date, or have friends, they ruin each chance I get along side not letting me go places. If I do get the chance to sneak out, they call constantly to see what I'm doing. I try not to do things out of line because, honestly, they scare me but if I don't go I'll never live my life. I don't even know how to do regular adult things like file taxes and such.

I have an opportunity to move in with my boyfriend but in not exactly sure how to go about it. Should I give them a notice? Do I just pack my things and go without telling them? If I do tell them I'm afraid they won't let me go at all. They flipped their shit when I told them I wanted to move back on campus... I'm in desperate need of help.