If you can make one at a time CORRECTLY, then do it that way. Then you won't have to scrap the entire project. It may take a little longer . . . but it seems like you've been spending lots more time UNsewing... KWIM?
OR - put the next color strip on - DOUBLE CHECK IT CAREFULLY AGAINST THE ONE YOU MADE CORRECTLY - then continue sewing the others. Line things up next to your sewing machine so you grab in the same way each time you go to sew the next strip on.
Good Luck!