Lots of questions on this thread.
As to the most recent. If you have gone to confession and recieved absolution, but forgot to confess a Mortal Sin, you were absolved of that sin, as long as you did not wilfully omit it. If you just did not remember it, don’t worry it’s been absovled. You can in a furture confession mention that in a previous confession you forgot to mention x, y, or z mortal sin, but be assured that it is already forgiven.
If you are guilty of Mortal Sin(s) and have not confessed and recieved absolution, make a spiritual communion at Mass. By doing so you can use the prayer found in most prayerbooks and missals which expresses that you cannot recieve our Lord in the Most Blessed Sacrament now, but wish that He come to you spiritually. You can also do the same if you are lawfully impeded from assisting at Mass, or if your workday schedule during the week prevents you from assisting at daily Mass.
Check your local parishes. One of the parishes in my area has Confessions on Wednesday night before the evening Mass, and Saturdays. Another has Thursdays and Saturdays, plus there is always an appointment for confession.
Lastly as this involves the Blessed Sacrament. If you can’t go to a church where the Blessed Sacrament is reserved, you can offer a prayer giving honor to the Blessed Sacrament in all the tabernacles thtroughout the world. Some even send their Gurardian Angel to adore our Lord for them when they are undergoing great trials, and cannot be in the church themselves. Remember as they are not limited by time and space, your guardian Angel can be before the face of God interceeding for you, at your side and before the Blessed Sacrament simultaniously, so you are not alone when you task him to visit our Lord for you.