9 months pregnant & a mental breakdown

I was cooking dinner last night and nothing was going right. It was turning out a mess and I hadn't taken anything else out. I was already starving from not eating much during the day and was feeling frustrated. My patience has been at an all time low lately and I started to snap. My s.o was telling me to just cook something else but I explaining to him there WAS nothing else. We've been without a car since it's been in the shop and unable to go to the store. I began to cry as I cooked him and my son something else. He kept pushing my buttons and I told him just to leave me alone. He kept pesturing me "what's wrong with you?" "Why are you crying" "why are you freaking out" and those questions just made me even more angry. So I continued to cook while I cried and when I was done he made a comment about his small dinner. I nearly killed him..but before I reached for a knife, I walked away instead and locked myself in the bedroom. I was sitting there crying and I don't even know why. I just kept crying and couldn't stop. After I calmed down I walked back out and my s.o came over to me, hugged me and apologized and the waterworks began again. He asked me why I was crying and I couldn't give an answer. I was a mess. I told him maybe I'm worried about the upcoming surgery I'm having in a weeks time. (C-section) and that's all I can think about. He has to take a week or more off of workto help me while I recover and that's another worry, because no pay. I'm worried I won't be able to handle juggling a newborn, a toddler, chores, cooking, errands etc. I told him I think the realization is setting in of how different life is going to be and I'm scared. He keeps asking me why I'm so worried, he's going ti be here, but he works fulltime with a day off so the majority I'll be alone. It's just alot I'm now focusing on being so close to my due date. It's terrifying. I'm scared of my surgery and the mostly the recovery. I went into postpartum depression with my last and afraid that might happen again. I'm scared it might happen more this time around being how sensitive and sad I've been.