Take care of yourself
The health of your relationship is affected by your own health. If you do things to take care of yourself, you will have more good energy to put into the health of your relationship. A mnemonic that I have heard of judging whether you are in a good state to have a conversation is HALT. If you are Hungry, Angry, Lonely or Tired, it is likely that things won’t go well in a conversation.
I had this happen to me last year. Before the event, I had had a several months long period where I had trouble sleeping. Not minor trouble, major problems. I realize now, in retrospect, that that contributed to an incident with a person close to me where I acted in ways I am not proud of. Instead of reacting calmly to something he said, I replied in a mocking tone. I don’t think I have ever done that before. And it caused major problems! He got extremely angry (I don’t blame him) and it put a hole in our relationship.
If I could go back now, realizing what I know now, how do I wish I had handled things differently?
I wish that I had realized that I wasn’t acting normally because I was so tired and stopped myself before I said it. Here’s some words I wish I had had ”I am not feeling well because I am not sleeping well and I am not up to giving this the attention it deserves. Can we pick up this conversation later?” Alternatively, when it came out of my mouth, I could have apologized immediately.
A related topic is how to set boundaries. Setting boundaries is a way of taking care of yourself. If you are in a conversation that is harming you (causing you stress or if you are being treated poorly). You can get out if it. I talked about that topic here.