Buddhist practice metta bhavana or loving kindness
It's the time of the year for kindness, compassion and gratitude to yourself and others.
Loving kindness to oneself, is about being realistic and knowing your limits, how much you can give and your boundaries. If you have the rising feeling that you are giving and giving and resentment is building up, take this as a sign that you need to spend time being kind and loving to yourself.
Buddhism, which the mindfulness field has mostly drawn from, works from the principle that kindness always needs to start at home. You can only really be there for others if you have a strong foundation of self-love, self-kindness and confidence to tap into.