OK you may not want to hear this but just try and understand things from her point of view.
She messaged you all happy and wanting to see you :
you dampened her enthusiasm ( you got out of bed the wrong side - as you acknowledge).
you told her you didn't want to see her at 1pm - then you would rather work than see her at all!
you sent her a 'gigantic series of messages' but apparently no apology(?)
you flipped.
( bet all that went down well . I'm not surprised she hasn't replied to you. I should think she doesn't know what to say, what you want - you're so erratic and bad tempered.
then you tell us youve told her:
she's emotionally immature
how replaceable she is
you won't tolerate her behavior.
What! What were you thinking of? You insult her and belittle her and then wonder why she's 'emotional'??? It's a wonder she still been seeing you at all. She must have the patience of an angel.
You tell us :
that you're losing interest
you're very upset
it's a sub par relationship
you may have been a bit ranty
you'll soon get over her when you're kissing someone else.
So do you or do you not want to make up with her?
It strikes me that you need to grow up a lot before you can have a relationship with anyone. You seem to be able to misinterpret things very easily, ( as you acknowledge), you can't control yourself, that you are quite unconcerned about hurting other people's feelings and insulting them, you are not self aware.
If she's any sense she'll have decided you're too much trouble.
Now the good bits. It does seem as though somewhere in the back of your mind you do have an inkling that you have behaved badly on occasion. Now you need to learn from all this. If you have slanging matches with people, it won't improve matters, if you criticise them, insult them, it won't go down well. ( Amazingly.)
Golden rules. If you can't say something nice, keep your mouth shut. Don't retaliate - it's very babyish.
You are supposed to have a relationship to be nice to each other, not score points off each other. You are supposed to make her happy not criticise her, put her down. Good luck.