You can remind yourself that this pain and fatigue will pass. The horrible moods that come with it, too. The brain fog will lift enough to be able to make sense of things, at some point soon. Your self control will return, with your self worth, and basic contentedness - just a few days away.
You can remind yourself that it's ok to not be perfect. It's human to mess up. It's normal to have problems in relationships. You are not a terrible person just because you struggle to get it right. You are just like everyone else. Not terrible, not perfect.
You do get it right some days. You got it right a lot in the past. Social grace is tricky to perform when brain fog filters out so much information. With less information, it's very hard to find the right answer.
You can remind yourself to be patient. It takes time to learn how to manage difficult situations. And it's difficult to learn while you're so ill.
You haven't done anything so bad that it needs urgent attention or the world will collapse. You haven't done anything so bad it's criminal. You haven't done anything that can't be mended, when you're a little better and if they can have a little compassion.
You can be compassionate to yourself. You are dealing with a lot right now. It would be a lot for anyone. The way out of this is to feel better, and that can only happen with rest, and that happens better when you're not obsessing over how to make things right in relationships. You can let go. Breathe. The problem will be much easier to solve when you have your wits about you. Your wits will come back. Let yourself rest.
Cut yourself some slack. Being so hard on yourself doesn't help.