Your situation isn't unique; college students often face questions they've never thought about before -- questions that make them doubt their faith, or even toss it overboard. And doubt isn't the only problem; often it's simply a matter of social pressure or being away from home for the first time.
Let me ask you a question: What are you doing with your doubts? Are you seeking answers to them, or are you content to let them take root in your mind and soul? To be frank, it's often easier to enjoy your doubts and let them grow (and one way to do that is to stop going to church). There's also something exhilarating about leaving your childish ways behind, including your immature faith.
But doubt will never lead you to the life God has for you, and that's why I hope your doubts will spur you to seek answers. And there are answers to be found; some of the greatest minds in history have been believers. Your parents may not understand everything that's going on in your life right now, but they'll be grateful if you're honestly seeking answers.
Most of all, I urge you to look at Jesus Christ, because through Him we can come to know God. At Christmas, we remember that He was God in human flesh -- and because of that, the Bible says, in Him "are hidden all the treasures of wisdom and knowledge" (Colossians 2:3).