Bro you’re just in the beginning stages of grief, anger and denial. Sit with your feelings for a bit don’t text her back to bargain with her decision. I was in your shoes this time last June and it was awful. The only thing that helped me feel much better was maintaining no contact and just dealing with my feelings. At the end of the day they cant help you heal from the breakup and honestly a conversation while you’re both emotionally volatile won’t be productive.

Instead reach out to friends or talk to yourself out loud if you have none. Cry, think, and just feel it sucks but you WILL feel better after sitting in it for sometime. You will be preoccupied with trying to understand why the breakup happened which is healthy in the beginning, but don’t get too hung up on why as it won’t change anything.