brewmama,
re: "...the Apostles and early Jewish Christians...met with each other on Sunday for church."
Actually, as far as the Bible is concerned, there are only two times mentioned with regard to anybody getting together on the first (day) of the week - John 20:19 and Acts 20:7. There is never any mention of them ever again being together on the first. The John reference has them together in a closed room after the crucifixion because they were afraid of their fellow Jews. Nothing is said about a celebration, worship service or day of rest. The Acts reference has them together because Paul happened to be in town and he wanted to talk to them before he had to leave again. The breaking of bread mentioned (even if it were referring to the Lord's Supper) had nothing to do with placing a special emphasis on the first (day) because Acts 2:46 says that they broke bread every day.
re: "'Now concerning the collection for the saints, as I directed the churches of Galatia, so do you also. On the first day of every week let each one of you put aside and save, as he may prosper, that no collections be made when I come.' (1 Cor 16:1-2)"
I assume that you're using 1 Corinthians 16:2 to support your notion that NT Christians observed the first day of the week for their day of rest and worship. However, there is nothing in the verse that indicates that. The text merely says that everyone should "lay by him in store" on the first day of the week. The Darby Translation reads: "On the first of the week let each of you put by at home, laying up in whatever degree he may have prospered, that there may be no collections when I come". The New Swedish and Norwegian Bibles read: "At home by himself". The Lamsa Translation reads: "Let each of you put aside and keep in his house". The Wemouth reads: "Let each of you put on one side and store up at his home". Ballantine's Translation reads: "Let each of you lay up at home". The Syriac, on this passage reads: "Let every one of you lay aside and preserve at home". And the New Catholic Edition of the Bible reads: ".......let each one of you put aside at home and lay up whatever he has a mind to". This verse says nothing about going to church for worship on the first day or even assembling together on the first day of the week.