Taking care of ourselves means not taking care of everybody else*. One tiny way to do this is to simply not justify yourself. You don't need anybody's permission and they don't need your reassurance/excuse.
*A cool side effect of this is that if you take care of yourself, you start expecting that everyone else is taking care of themselves, so the urge to take care of other people lessens naturally.
Here's how it works:
Hey Johannah, are you coming to yoga tonight?
No, I can't. Have fun though, tell everyone I say hi.
No, I'm not, have a great time!
I don't think so – I hope it’s good!
No, are you?
I am not.
BUT NEVER NOT ONCE
No, I have so much to do, I am just swamped. I really wish I could. What are you guys doing after? Let me know, maybe I can meet up if I finish my work by then. Hopefully I can come next week!
Note: there are many situations in which it is important to give somebody extra information. But this isn't justification. When a wife says to her husband, "I won't be able to stop at the pharmacy on the way home; I have to work late." It's an explanation that supports the partnership.
Today, practice declining without justifying.
You are awesome,