Dear mikasa5ever~
I'd like to welcome you here to the Forum, and hope talking to others here helps.
Getting that message via Discord must have been a shock, you do not mention that you had been feeling things were not going well beforehand so I guess this is simply how she feels.
Sending a long message does indicate that the relationship at the very least had meant something to her, but a long text message is probably not the best way to explain one's feelings, face to face might have been better.
As you have been apart for a while at different schools things may have changed for her, though you made be the same. You had plans on both going to uni and living together, maybe she has changed her mind on that, it's hard to say - and that's just a guess.
In fact guessing why things have turned out this way is one of the hard things to endure, as is the sense of loss and greif.
What to do? Well you could ask to meet face to face and talk over the separation, you might learn more if she is willing to meet, however it does not sound like it would go any further than that, so you would not be much further ahead.
You may have mutual freinds who might be able to give more reasons -a new boyfriend perhaps?
Trying to find out what happened is a natural thing which is why I mention it, however it is your future life that is the really important thing, getting you to the stage you can cope, and even do better at maths:)
I don't know of any quick easy path, however I would suggest you contact The Kid's Help Line, by phone or web-chat. They are extremely experienced with all aspects of problems of young people and may be able to give you better suggestions that I can.
One's first love is special, and even when your life has changed and you are happy again it will still be something you remember, as do I with mine. The hurt does go though (hard to believe ATM), driven out by subsequent events, experiences and relationships.
Do you have anyone in your life to support you, just listen and care -not "fix"? Maybe a family member or another friend or a school counselor?
As for the world going up in flames, this comes from media, TV, even newspapers. All paint the worst and most frightening picture posssible because it attracts and keeps viewers, not because it is all true. I expect you realise this already, advertisements and vested interests rule. I steer clear of it all and have quieter and more stable life as a result, no longer spending so much time hearing and stressing about of horrible things I can do nothing about.
After my fist relationship broke up, I too was at school, I thought that was it, things would never get better -I was wrong.
You know you will always be welcome here
Croix
