I need help... (Bf)

Uhm so last night my boyfriend and I were talking about something in the past that I had done and had really hurt him, and I know I am a terrible person for what I did, but we are working through it and I need to find closer for him as to why I did it and stuff, and so he was asking me about dates of when some of the stuff started to happen and I snapped at him, I'm on my period and I'm very bad on this topic because I hate thinking about how much pain I put him through and hate myself for it and I just snapped and yelled about how I couldn't remember and now he's not talking to me and I don't know what to do and I feel really bad and :(