Exactly. There is nothing in the Bible that authorizes the change. In fact, the Catholic Church has said so explicitly and takes pride in being the one who changed it from Saturday to Sunday.
Them having tradition AND scripture as foundations for doctrine, have no trouble reconciling their practices with their sources. And I think they're consistent on this point.
What I think is a big problem with doctrine in all protestant denominations is claiming they follow the Bible as they know it, and accepting without a secound thought this legacy of the church they separated from.
One can make up all sorts of fables about why Sabbath is Sunday now (such as that Jesus resurrected on Sunday) to justify it, but the plain truth is that the change originates with the Catholic church.
(I don't understand why the downvotes to my comment above. I'm just pointing out some interesting things, not trying to say someone "You're not going to heaven")
I really appreciate people with convictions. I can see that the Sabbath issue is important to you, I'd only like to point out that, if one is to take it seriously, it's important to realize Sabbath is, and always has been, Saturday, the seventh day of the week.