It is not a sin to not get married. Christ says that there are eunuchs who are so from birth, there are those that have been made to be eunuchs, and then there are those who are eunuchs for the kingdom of God.
Eunuchs for the kingdom of God - this is one thing that points to a vow of celibacy. I am Catholic, and our priests, brothers, and sisters all take vows of celibacy for the kingdom of God. We also have lay persons who are called consecrated who take vows of celibacy. Some who have a same sex attraction, out of respect for marriage, live celibate lives.
If you wish to build up the Body of Christ via your celibacy, and devote your life to the church, then that is one thing. If you are afraid of intimacy, rejection, commitment, marriage, etc, or have a psychological disposition toward it because of a previous experience/s, that is another matter all together.
Many are called to marriage. Others are not. I myself feel as if God is calling me to the priesthood. Does this mean that I dont want to get married? No. It is a great struggle to me, and involves a sacrifice if I do enter the priesthood. We are all called, based on our gender, to be husbands, fathers, and brothers, or wives, mothers, and sisters. The question is, in what way. As a priest, I am a shepherd to a flock, and a father in this way. I am also their brother in Christ. Make sense? Whether married or celibate, I must still live out these calls.
So I guess it comes down to, why dont you want to get married? What about it repulses you? Have you had any previous experiences with bad marriages, in which there was abuse, etc (parents, parents relationships after a divorce, aunts and uncles, grandparents, friends' parents, etc?)?
God bless