Have you tried to put yourself in their shoes? Your parents are obviously committed to their church tradition, and one of their hopes as they raised you was that you would become committed to it also. But now that you've chosen another way, they don't believe you are simply rejecting their church, but you are rejecting them and the way they raised you.
This wasn't your intention, however, and somehow I hope you can express this to them. Let them know you love them, and that you're grateful for all they did to raise you. Thank them also for raising you in their church; after all, even if you didn't find Christ there, you still learned to believe in God. What if you had grown up with absolutely no religious background (as many do)? Your path to faith in Christ might well have been harder.
At the same time, I'm thankful Christ has become real to you, and that He has led you to a fellowship of believers where you can grow spiritually. The Bible says, "Let us not give up meeting together ... but let us encourage one another" (Hebrews 10:25).
Pray for your parents, and ask God to help you be a witness to His love by your life and your words. Remind them that only Christ can save us; He is our hope of salvation. The Bible says, "Always be prepared to give an answer ... for the hope that you have. But do this with gentleness and respect" (1 Peter 3:15).