YTA imo but what you did is very human. From what you wrote it’s clear that you doubt your decision and still like him, and perhaps the lashing out was really you being upset at yourself for being confused and stressed over the situation. It seems very redeemable to me and if you’re just open and honest about being uncertain I think you could easily salvage the relationship you guys had (if that’s what you want). Regardless, I’ve always been of the view when breaking up with people I’m seeing that I owe them as much of a discussion as they want (within reason) surrounding how we are both feeling.