Good questions!
…Why do you believe in your faith?
Because God called me to Himself, and He had promised to give His Church the Spirit of Truth, who would lead the Church into all truths, and He gave the Spirit on Pentecost, giving birth to the Church, and the Spirit leads the Church into all truths, deepening our understanding of the mysteries of our faith, and because the Spirit is God, and God is the truth, and the truth can not decieve nor be decieved, I know that the Church, guided by the Spirit of God, cannot deceive nor be decieved in her teachings, i.e., she is unable to error in faith and moral, that is, she is infallible. And that is why I believe in the Catholic Faith.
…Why do/did you doubt that faith/portions of it?
Many are tempted to doubt, but not all given into doubt.
…What changed your mind about those doubts?
I have doubted many times, but each time God has reminded me of the truths professed by the Catholic Church, and so, I come back to my senses.*
…What makes you positive your faith is right and that all others are wrong?
Because the Catholic Church is infallible, and her teachings, far from being grounded in belief and imagination and visions and dreams, are actually grounded in history, reality, and truth. They are grounded in history because, first all, Jesus is risen from the dead, and all else is grounded in history because of the historical existence of the prophets and persons of the Bible and the saints and martyrs of the Church, though many legends do surround them (but legends do equal historicity); they are grounded in reality because, first of all, God is reality and He has created a space-time contiuum, and what He dose He dose really, it is no myth nor illusion nor something which is simply nature, though He works through His creation and through His creatures (solar eclipses, evolution, etc.); and they are grounded in truth because, first of all, Jesus is God and God is the truth itself, and all else is grounded in truth because God has, throughout history, permitted evil to bring out greater goods - for example, the death of Jesus to bring out the redemption of man - and acted as the Lord of history in bringing certain events to light in order to teach His People about Himself and His Will and His works, ultimately for their salvation and the salvation of the whole wide world through them (for God is Salvation and He works through His Body, that is, His People, whom He has made His Bride via the covenant, and just as a husband and wife become united through sexual intercourse, so too has God and His People become one through covenant).
As far as other faiths being wrong, they are only wrong in as far as they deny or reject what is the truth, and they are correct when they accept and acknowledge what is the truth. All faiths share in the truth, to a degree or another, and the Catholic Faith, because it is the fulfillment of the Jewish faith, has the fullness of the truth. This isn’t to say that all other faiths share in the Catholic faith to a degree or another, but rather, that they, like Catholicism, adhere to the absolute truth to a degree or another. No religion is a monopoly on truth. The truth trascends mankind, because God is the truth. (Sorry for repeating myself)
…What is appealing to the faith?
Holiness, justice, love and mercy: for the Church is Holy, and she is just, loving and merciful, a true shining image of the Lord, who’s attributes are holiness, justice, and love and mercy.
…Why do others follow this faith?
Because they see the beauty of the Catholic Faith and know that is founded on history, reality, and truth. By beauty I mean the holiness, justice, love and mercy of the Church and the truthfulness of the Faith and the art and icons of Christianity. Though there have been many who do evil yet call themselves Christian, the triune Church is holy, resembling the Holy Trinity and foreshadowed by the Holy Family, and the Church, like a good mother, claspes sinners - for we are all sinners - to her bosom.
…What do you do if you disagree with something in the faith?
You mean if you’re not sure with something? You see if the Church teaches it. And if the Church dose but you don’t agree that it is true, than you must swallow your self-love and submit to God. We may not understand everything, but that dosen’t mean we shouldn’t follow God. Some would say we are blind who follow the blind, but God is not blind - He is shining light, the light of the world.
…What makes you happy/content with this faith?
The Catholic Faith is founded on truth, reality, and history. God is my happiness. Religion is a virtue, it is man’s response to God, it is him giving what belongs to God. The fruits of this virtue are prayer, fasting, and almsgiving - that is, prayer, sacrifice, and charity, or, to put it even simplier terms, living in God (God is love). Man must give to his Creator and Redeemer what he owes Him, simply out of justice, and dose so by returning love for love and mercy for mercy, just as man must “give to Caeser what belongs to Caeser”.
…Is it possible for you to accept others and their faith, even if it opposes your own?
As Christians, we are called to charity. If we do not love, we are not Christians but liars, for if we say we love God but hate our brothers, than we do not truly love God, because we must love our neighbors as ourselves - we must become neighbors for others - in accordance to the commandment of charity: love of God and love of man.