Depends on if any "mortal sins" were commited. It would seem to me that if you were instructed in the faith and then walked away from it, you most likely commited mortal sin....missing Mass, being only one mortal sin...maybe more. There isn't a sin that just about any priest hasn't heard before. Go to confession and get your soul "cleaned up". Remember...you're not telling your sins to a man...you're telling to Jesus. Jesus works through the priest. It is Jesus, acting through the priest that absolves you from your sins. You than tell Jesus that you are sorry and that you will do your best not to commit those sins again. There are several resources for making an "examination of conscience". The best one I could recommend is a tape/CD of Fr. Caropi. He does an excellent lesson on how to go to confession. I just saw the tape last week...it's excellent. Sorry for the amt of bandwidth consumed....just wanted to help.
Thanks for the reply, Russ.
I will check into the tape you mentioned.