Hi,
When you see the priest before Mass, ask him to hear you Confession. You need to receive absolution as soon as possible. Whether you serve or not is not important compared to your need to receive absolution. It’s ok to read or serve, but do not receive Holy Communion in the state of mortal sin. If the priest can’t help you until after Mass, then confess after Mass. But don’t let a week go by. You are in my prayers.
Fr. Vincent Serpa, O.P.