I need to break-up with my girlfriend but I am scared for my life...How can I do it?

My girlfriend and I have been dating for a little over a month now. At this early stage, we have gone through some rough patches and also, a pregnancy scare. We were classmates 2 years prior to us dating. At first I was really attracted to her but soon realized that we think and live at different bandwidths. Everytime I tick her off about the smallest things like failing to reply to her text messages, or supposedly being "selfish" and mentioning "breaking up for the better" she threatens me that her former police officer dad's gonna send out a bunch of thugs to kill me. That scares me a lot and I don't think that this is a healthy relationship at all.I really don't know if it's still love that I am feeling for her, or lust, or fear..I just want to get out of this mess. Not putting all the blame on her, it was also my fault I got into this. A bunch of stuff has made me lonely and not thinking clearly these past few months...I needed someone to cling to and she was there. I lost someone very dear to me and is now losing another one in a sense (someone close to me is having severe depression). I know this may sound insensitive but I have gone as far as to planning to feign schizophrenia just get out of this. I just want to be alone now and hang out with old friends. Any help on this matter would be greatly appreciated. Thank You!