It’s taken me many years to be able to say no without explanation. It’s ok to take care of yourself first, and if saying yes to someone or something you know will deplete your energy or resources, then it’s not only ok to say no, it’s absolutely necessary. Once you’ve established boundaries that will protect your well-being, others will respect those boundaries. They will eventually get the message that you’re just not available! It’s not selfish to take care of you first!