Having doubts and questioning aspects of the Faith are not in and of themselves sinful. Nor do they make one a Formal or Material heretic. However in the position you find yourself in, I would say finding a good Spiritual Director and reading why the Church takes the position it does would be a good step for you.
You are correct that as Catholics, we are bidden to love the sinner and hate the sin. In the arena of Morals, this would include Homosexual or Heterosexual abuses of sexual expression.