So about a month ago my girlfriend and I had an argument in which I yelled and told her that I thought her dad was a **** idiot. She was quiet the whole ride home and I told her to go sleep at her own place that night. Her dad had basically broken my balls in front of her and was acting like an in general.

I sent her text after text and called and called her after she texted me that we were done the next day. No reply. Only thing I have heard from her since is that she needed her apt key back. I have sent her numerous texts and emails and called a few times since. One of the emails was a sincere, heartfelt apology to let her know why I acted like I did and how I had taken her for granted lately. I also said how I wanted to spend my life with her. I know she is reading these but she isn't responding. How should I proceed?

It sounds like you finalized the relationship about a month ago. Move on. It doesn't sound like she's interested in you any longer or wants to be part of your life. (I don't blame her.)

You apologized and she has not responded. There is nothing left for you to do but move on.
She has made it clear that she is done.

You apologized and she has not responded. There is nothing left for you to do but move on.
She has made it clear that she is done.

I should mention that I only sent the apology about a week ago. Also, it is strange because the day before this happened we had a great night and she said I was the best thing to ever happen to her.

She asked for her key back and has not responded to you.
You leave her alone. Don't contact her again, that would only seem like stalking. There really isn't anymore you should do except to just leave her alone.
The next move is hers to make if she wants you back.

She asked for her key back and has not responded to you.
You leave her alone. Don't contact her again, that would only seem like stalking. There really isn't anymore you should do except to just leave her alone.
The next move is hers to make if she wants you back.

Thank you for the advice. I will definitely not initiate any more contact. The ball is in her court.

She may have said don't text me ever or she may just be mad. Not everyone would say I don't ever want to see you again. At any rate the ball is in her court. She will contact you if she wants.