I don’t think Christianity forbids you to love yourself. Your love for yourself is presupposed. Jesus said the second greatest commandment is “You shall love your neighbor as yourself.”
But it must be in perspective. The first greatest commandment is, “Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy mind.”
Should be in this order
Jesus
Others
Yourself
(note the first letters)