Sorry you are disappointed at your results. A square pattern isn't the best choice for a bed quilt though. That pattern looks like it's 82 square for the "medium" size. A queen mattress is 60x80, so it won't have enough drop to fit if that is the look you wanted. You would have had to make the "large" one, which would fit more like a bedspread than a quilt. I have a 100" square on my queen bed and it's quite large. Probably 90 or 92 square would have fit mine better, but I do have a thinner mattress now than when I made the quilt, so it does fit a bit different than it used to.
Another idea would be to add another row of blocks, then borders. Or you could use it over another quilt and put the square on the diagonal as a decorative effect, or fold it at the foot or over a footboard. In the future, you might want to choose a pattern that is already designed as a rectangle, and large enough for the bed.