@Matthew The quick answer is yes. You are still Catholic as far as the Church is concerned. So called "fallen-away" Catholics return to the Church every day via the confessional. For that, we all rejoice! Just come with a contrite heart, confess all your mortal sins, and sincerely intend to amend your life.
The less quick (and better) answer, to take into account all the specifics of your situation, is to speak with a priest. Often making an appointment works best (for sufficient time).