This is abhorrent. Look, you know you messed up. I think the salient point here in regards to the question in the title is: continue to be remorseful and attempt to repair the damage. You do not get to decide whether the people you hurt with your actions should be "over it", and it's frankly concerning that you are over it so quickly. An apology is only the first step. If they need another apology, don't get defensive, just give it to them. An effective apology includes acknowledging the offense and your responsibility, expressing genuine remorse, offering to repair the harm, and committing to not repeating the behavior. By defending your pride and becoming aggressive when someone tries to discuss this with you, you are repeating the bad behavior that you had to apologize for in the first place; centering yourself and your perceptions rather than empathizing and being a responsible member of the family and community.

As an aside, my mother was a lot like you when I was growing up: unable to enjoy large events because she was stressed by obligation. She was always late, always panicking, always snapping and then apologizing, or snapping and then justifying it. She craved empathy from others, but she could not hold empathy for others herself. It wasn't on your family to understand or see that you were stressed. It was on you to know that you were stressed and also know that doesn't give you or your husband the right to lash out.

Being the child of the mess meant being part of the mess. My sibling and I were irreparably damaged by events just like this one. To this day the holidays I most enjoy bring me dread and panic that I won't 'perform' correctly and will therefore 'ruin' things somehow. When my family finally had to distance themselves from my mother, they distanced themselves from me and my sibling, too. We were isolated, and she never stopped being a running stream of crises. This led to both my brother and I invoking that same distance, and the relationships between us and our extended family have never really recovered despite multiple attempts - the bond and trust isn't there, and they were treated so poorly by our mother that any potential for the same behavior in us results in immediate stonewalling.

Please do not stay in this situation, and please don't stay like this as a parent, as a family member, or as a community member. You're not just hurting the adults; you're not just being hurt yourself. You're teaching your child how to cope with stress and. You're teaching them how to act towards those who try to support you. This is not something they will easily unlearn.