Help me get over him!

I was dating someone for a couple of months and I fell for him HARD.

We decided to see each exclusively, but keep it casual. Which I was okay with. Except he, I know unknowingly, wasn’t treating me fairly. But when I was with him, it was perfect.

This weekend I finally had enough and stood up for myself. Except I crossed a line and told him “I’m WAY out of your league anyway”. He was very polite, said goodbye and never replied again.

I sent him apology flowers (as a genuine apology. Not begging for him back or anything). Obviously didn’t hear back, and I wasn’t expecting to.

I’m deeply heartbroken and it feels like I can’t breathe. Clearly I haven’t done this in a while.

Any advice on how I can better deal with my emotions to move on?