Marriage and fighting

In my previous relationships fighting never got to me like it does now. With my ex we fought ALOT and it didn't bother me, at all. I didn't care about him as much, looking back, that I thought I did. Now I am happily married with the most amazing man! But when we do argue or disagree I get panicked. I get super stressed and I want him to forgive me so bad even if it isn't even my fault. I just want everything to be alright. He works nights and it seems like when we do argue it's before he goes to work. I am 15 weeks pregnant and tonight I drank half of a diet soda (which I don't usually do because of the caffeine and fake sugar). When he found out he got really mad at me! He wouldn't talk to me other than asking why I would drink that knowing how bad it is for me. I felt so crappy after! Now I can't sleep because we left things bad. He knows that if we argue before he goes to work it affects my night so I don't understand why he leaves with things tense. I felt so confused and upset that he got so mad over a small soda that I barely drank any of! My anxiety is through the roof when we disagree or argue, I don't know how to fix it. I instantly feel like our marriage is going to fall apart. I don't know why I feel like this when we barely argue! Maybe twice a month if that. It just hits me really hard.😔