Never feel guilty about your own self-care.  It’s extremely important to take time (real time) to focus on you.  At the end of that time spent of self-care you should feel more relaxed, or rejuvenated, or more whole, or prettier, or stronger, or more prepared for what lies ahead. Taking the time to engage in self-care ensures that you are the best version of you that you can be.  It is not at all selfish to put others on hold until this task is complete.  They too will benefit from this better version of you.