You sewed the whole thing with no bobbin thread?
Please DO NOT say you cut it by accident. I almost don't want to think about what you could have done....you didn't spill your drink on it did you?
One time when I was making my husband shirts...stupid me cut out the peices and THEN removed the pattern peices and folded the pieces up and set them aside. I needed fabric to cut the collar out and THOUGHT I had grabbed the left over fabric....but didn't. Instead, I had grabbed the peice of fabric that was the back peice that I had cut out and used it to cut the collar out. AFTER THE FACT....I went to sew the back to one of the front peices and seen what I did....I was so blasted heart sick and was not able to get any more of that fabric...since then I DO NOT for no reason whatsover remove pattern peices until ALL pieces are cut out and accounted for.