Many think that taking care of their needs before attending to other people's needs is selfish. The diminutive "ish" means to be like, ex. girl"ish", imp"ish". So if you are self"ish", you are acting like yourself. What if that meant that you are true and genuinely doing what is right for you when you are self"ish".
Experiment prioritizing your needs and see how it replenishes you.