He keeps hinting that we might break up and that he has to see how out goes it's all he can do
He has been weirdly distant for a couple of days about
All this fuss about something that happened last year that I can barely remember
The stress of it is literally giving me a panic attack because I feel so anxious
You are dealing with narcissism - he checks all the boxes.
This not a huge fuss over something that happened last year.
As a PP said, if you breathed before you met him he would create a problem over it. If you had a cat when you were a child he would find a way to kick up about it. If your favourite colour was yellow he would find a way to make you feel that was stupid. If you liked ballet flats he would scoff. Are you seeing a pattern?
What he is doing is testing you to see how much bullshit from him you are willing to put up with, and to see if he can get you hooked into his game. His game is to create a massive fuss over something minor, to make you feel you have done something really wrong, messed up spectacularly, so you are on the wrong foot and find yourself trying to explain normal everyday life to someone who can't seem to understand any of it. You are even trying to explain it all to people here. He has really got under your skin.
He loves seeing you working hard to please him, turning yourself inside out with worry and anxiety that you have displeased him, fearing that he might break up with you unless you get everything right. He has somehow convinced you that he is too good for you.
In this relationship the only feeling he seeks is a feeling of power over you. He has no actual feelings for you. The relationship isn't important for him as a source of love, affection, or anything else that's normal.
He is getting a huge rush from seeing you anxious, confused, and upset.
This is what you have to look forward to forever if you stay in this relationship.