Sometimes clients are so used to doing for others that they have a hard time devoting time and financial resources to themselves. If that is you, it might be worth asking yourself whether you consider yourself to be equal to those that you have been putting first. You don’t need to think of yourself as more important than them, just equal, in order to notice that of course you deserve to be treated as well as you treat them.
If you still have trouble doing something for yourself, you could try taking the broad view that taking good care of yourself benefits others because by nourishing your health, you will have more to share with others.