Hey Seth, it's very nice to meet you. My name is Luoma, and I want to firstly welcome you to the forums! I hope you find the care and support you are looking for here.
I usually give the same advice to everyone who is having a breakup, but that's because it's good advice. Seth, I know everything seems like it's falling apart. I know you feel as if she was the only one you could ever possibly love. And it might be hard to accept, but I want to tell you that there will be other people who come along in your life. There can be another girl who can treat you the same way, or can help be your rock later on in life. Or perhaps you're not going to date them, but there can be new friends, too, who can help ease the pain of losing her.
The most important thing is to not focus on that and take time for yourself. Let yourself heal, okay?
And like May said above, it's possible that you two could technically get back together, but you do need to sort out your inner pain first. I know it's hard. But, in a week, you'll notice that the pain of losing her will eventually start to go down little by little. You just have to keep fighting, and keep pushing forwards. I'm sure it wasn't easy for her either, but it's not good to be in a relationship where there's arguing, for both you and for her. Because later on in life, that arguing becomes really, really toxic and you don't want a marriage ruined and kids caught in the middle.
Also, I know it's hard to look forwards, but is it possible that you two could be friends in the future? You don't have to do so right now, because I know that it must be so hard to see her, but in the future perhaps you two could still be friends so she could still support you like she used to.
I wanna wish you the best, okay? stay strong and stay safe. It gets better. -hug-