This fellow (a priest) explained it pretty well here:
*TWO KINDS OF SELF-LOVE
By Father Paul A. Duffner, O.P.
Whenever we hear the expression “self-love,” it usually conveys the concept of selfishness. If one would make the remark: “He certainly loves himself,” that is usually not meant as a compliment; but rather refers to one who has an exaggerated idea of his own excellence, or one who is solely concerned about his own welfare with little concern for others, etc.
Yet, love of self, if rightly understood, is something that is not only good, but commanded by God:
“You shall love the Lord your God with your whole heart, with your whole soul, with all your mind. This is the greatest and first commandment. The second is like it: You shall love your neighbor as yourself” (Mk. 22:37).
When our first parents were created by God, they had the kind of perfect love described above by Our Savior. That is, they had the capacity for that perfect love of God, self and neighbor; and there was nothing inherent in their human nature that interfered with the exercise of that perfect love. But among the gifts that God had given them was a free will. They had to freely choose God’s will, God’s plan for their life. And before admitting them to the eternal beatitude for which He had created them, God put them to the test. Theirs was not an absolute freedom, for God placed a limitation to their dominion over all that He had created. (For a detailed account of this, cf. Vol. 40, n.1). In their failure to pass that test, they rebelled against the limitation God had placed on their freedom, and they not only lost divine grace and the capacity to love with a supernatural love, but their intellect was obscured, their will weakened, and they were left with an inclination to selfishness, a tendency to seek their own will rather than God’s; that is, an inclination to inordinate self-love.
So we have the rightly ordered love of self which God commanded, and the inordinate love of self to which we are all inclined by reason of our wounded human nature. The whole of the Christian life is a struggle to overcome the latter in order to attain the former.
TRUE SELF LOVE
The “rightly ordered love of self” that Christ commanded is a love of self whereby man wills and seeks his own true good, both spiritual and temporal. It is a love guided by right reason and the truths of divine faith. It is the love of charity. The good that the Christian wills for himself is primarily God Himself (Whom he possesses when in the state of grace), and the eternal beatitude with Him in the life to come. And, secondarily, true self love has for its object the sanctification and salvation of his own soul and that of his neighbor. From this it is clear that man loves himself in the true Christian sense in the measure that he avoids sin and exercises the Christian virtues, making good use of the sacraments that God provided for our spiritual needs.** It is obvious, then, that true love of self demands discipline and self-denial in regard to our unruly self-seeking tendencies.** Fr. Alfonso d’Amato, O.P. brings this out in speaking of the commandment of love:
“In practice,** to love ourselves means above all to combat our natural egoism which tends to impoverish our nature, to shrink it, to hinder its expansion towards our brothers and its fulfillment in God**. True love of self should push us to work indefatigably to be fully ourselves, to realize the perfection which is the fullness of our being, as God views it from eternity. Now the chief obstacle to this true love of self is a false love, egoism, which makes us lose sight of the model, the ideal to be attained, lowers our aspirations and makes our existence miserable”(The One Commandment, Cross & Crown, Dec. 1952).
True Christian love of self also causes men to seek such temporal goods as are required for the well-being of the body: suitable food and clothing, shelter, lawful pleasures, etc. But these are sought not as an end in themselves, but insofar as needed for the attainment of the soul’s sanctification and salvation.
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TRUE LOVE OF SELF AND LOVE OF NEIGHBOR INSEPARABLE
**Since Christian love of self is the love of charity (which must include love of God, of self and of neighbor), we cannot love ourselves truly without loving God and our neighbor for His sake. **We love ourselves when we love our neighbor, not only because it is our duty (and fulfilling our duty is a requisite for true love of self), but also because it redounds to our good, since we are members of the same body. As St. Paul explains, “If one member suffers anything, all members suffer with it; and if one member glories, all members rejoice with it” (1 Cor. 12:26). …
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FALSE SELF LOVE
In contrast with true Christian love of self there is inordinate self love, in which one is guided by one’s own likes and dislikes instead of by right reason and the will of God. Such self love often causes one to seek the gratification of one’s sense appetites and the pleasures of the body in a way contrary to the good of the soul and to the law of God. Inordinate self love will at times manifest itself in a spirit of rebellion against lawful authority, or in extreme pride in one’s good qualities, achievements or possessions as if one were the sole source of those goods or good deeds. Such a one is oblivious of the warning of St. Paul: “What have you that you have not received and if you have received it, why do you boast as if you had not received it?” (1 Cor. 4:7)
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rosary-center.org/ll49n1.htm