sewlilly

I'm in the middle of applicating some letters with a blanket stitch and I'm almost through, but all of a sudden I'm stuck in reverse! I tried to just sew in reverse, but the stitching isn't quite right! It only goes backward on this particular stitch - I can straight sew forward.

Help!!

I have an older machine that I bought some 30 something years ago from JC Penney - I've never had this problem before.