Sometimes people take what is said in the Bible a little too literally. One of the best is the 7th day-off thing. It's like the built in "cheat day" with dieting. Many people think Sunday is an unconditional day of rest. Quite simply, it's an excuse.
When the good Lord said this, he was leading by example. He created the heavens and earth in six days. He worked. And he worked hard for six days. He earned that day off.
When he said rest on the 7th day, I don't think he was talking to the people who didn't show up days one through six. Or better yet, the one's who showed up but didn't accomplish anything.
Point is, if you want to accomplish anything great you have to work. I didn't say accomplish anything average, I said GREAT. You have to be focused and committed to the process EVERY DAY. I don't know one successful person who had a work filter or refused to work on Sunday.
If you think you did everything possible to move towards your goals, Monday - Saturday, give yourself a little rest time. But I'm betting even if you did, Sunday is no different to you than any other day. You just do what you've got to do to get it done.