I was also in your position and would just advise you to go to confession and say to the priest how long it’s been and that you need help, and the priest himself will help you through it. Don’t worry about doing it wrong or any such thing. The only thing that God and the Church require is a repentant heart. If you have that, don’t delay and just go and ask the priest to help and he will gladly do so. You could also ask him to go through an examination of conscience to help you remember sins that you may have forgotten.
Do not be anxious or afraid, the Lord wants to grant you His peace as only He can give.