Where do I go from here? (Ex Girlfriend issues)

Hey guys I was wondering if anyone could guide my way through this a bit.
P.S. I know the easy thing to do here is to move on and forget about her, but lets be realistic. I'm going to try my damn hardest before I do that.

Well, I've been trying to get my ex back, and I have had some success, but suddenly it's gone completely south.

Things were looking promising, I was about to go in for "the kill" so to speak... but then suddenly she started posting pictures of "Leave the past in the past" quotes and all that crap about how "she misses the past, but it's best to keep it in the past."
I was like "woah wtf way to 180..." Then I figure out she's seeing someone new.
So, being an idiot, I stop no contact early.
I try to be her friend, it sort of works, but then I get impatient, and start asking her to hang out, etc.
Eventually she gets pissed off at me, and sends me a picture of this guy kissing her.

So yeah, that was nice.

As you'd expect I lost my absolute shit.
Called her every name in the book...you name it.
I even wished death on her.....I've never said anything like that to anyone before. The thought of those words escaping my mouth still haunt me.

Anyway, she hates me now it seems. However something strange is the fact that she "blocked me" on her phone, but the texts still go through... They didn't at first, but a few days later I tried texting her and it went through.
All I want to do is get her forgiveness

and I have literally no idea what to do from here.