What do i say ???

My boyfriend and I got into a huge fight which left him leaving…. We haven’t seen each other in almost a week . Yesterday was our first time talking since. He is upset I get it and so Am I . When we were arguing I told him *you don’t have the right to ask me that* meaning like where I was ! Idk why I even said that to him . He told me until he gets a explanation of why I said that then He’s Done ! I already told him, I’m sorry, I apologize for saying that, it was mean, hurtful etc. I also explained I was stressed out, having a bad day. I am lost for words right now since I’m not sure what made me say that to him at that point in time. How do i truly fix this….