I feel your pain. I once did a pieced border for a KING size quilt, hated it as my measurements were off because I didn't take into account all the bias edges of the key-west block. So, I let it rest a couple of days, then spent TWO DAYS ripping it out, then set it aside for a long time before deciding that a plain black border would look best to go with all the fabric in the quilt that had a black background, and it turned out nice. I had made the quilt for my husband for our 25th wedding anniversary, however, it "aged like fine wine" for10 years before I finished it,but I did finish it, and I really liked the plain black border, especially after quilting it witih a cable quilting design. Now if I could just figure out a way not to let my projects "age" so long, I'll be all set. LOL. If you don't think the second fabric you chose isn't right, take it out, give it a couple of days, then make a decision, it will all work out.