Yes, definitely tell your family or a few close friends that you plan to break up with her. Get some support, because you'll probably need it.

One of my best friends had a similar experience. Minus the physical abuse, his girlfriend would not let him even TALK to girls. She would constantly visit his workplace, even trying to get him to get her a job there, and when he told her he was unable to do it, she started a fight about how he just wants to "fuck all the little whores there" (at work)...

I also had a similar situation... I was 18 and my boyfriend was 20. (We started dating when I was 16 and he was 18). He was always really clingy, which I don't normally like, but I understood that that was just how he was, and it was kind of flattering. Well, after two years, the clingy-ness became controlling. He'd show up at my workplace often and ask about other guys I worked with. I specifically remember how he'd often call me up to 8 times in a row, and when I finally talked to him later, he'd start a fight asking me what was more important than him that I couldn't talk.

Speaking from both a firsthand and secondhand view, Get out - NOW. Physical abuse aside, she is abusing you emotionally and verbally, and is trying to control you. Leave asap. You'll have to deal with the shit for a while, but soon enough it will all be over and you'll be free of it.