Miles:
One of the People at my parish has the same problem, and his parents (esp. his mother) have made it difficult for him even to attend. His older brother went through much of the same stuff before his Confirmation, and his parents still try to argue against what he’s doing.
So, not only can I tell you to persevere, but I can also tell you that you aren’t alone, that others have gone through what you’re going through, and that others will go through what you’re going through.
Ask the people at your parish if they can help you talk to you parents or if they can point you to any resources to show them… and, All else fails, try showing your parents the passage from Galatians 5:19-23 comparing the “Acts/Works of the Flesh/Sinful Nature” verses the “Fruit of the Spirit” and then asking which they would rather see in their son.
Of course, as everyone here, I’ll pray for you - Your’e in a tough situation. I hope something here helps.
Your Brother in Christ, Michael