Lord Supper and the first day of the week

After sunset the day ends? We begin a new week on Saturday evening then?
Even if night is for resting we may also pray all night to conclude fasting day(s)?
How we can have communion at any of our meals?
Why we remember the new covenant of Christ by bread and grape juice?

Fasting 3 days and 1 night of prayer before breakfast for historic life changes

Holy Days

Which days are special for you and why you celebrate them?

How do you feel about people that give attention to certain days?