Yup, been there, done that !!! Your learning curve goes straight up !!!! I have learned to roughly figure out how much fabric they are calling for, for a quilt top. And when I figure they are asking for ( in your case,what you thought was 18 different pieces, 5/8 yds of each, whick works out to be 11 and 3/8ths yards of fabric), I think holy crap, that's way too much !!!! What am I thinking wrong???? Go back and read carefully!!!! Hope this helps, Auntie B in Saskatchewan, Canada.