Don't stress, put it aside, work on something else for a while and relax, I spray baste and sometimes I use the little tacking gun, which inserts tiny little plastic tags which I clip off when finished. The little tags are great as you can put them close together, it doesn't harm your machine if you sew over them and it's easier on your fingers than pinning. You may stretched your backing on the carpet and because your design is chevron which is cut on the bias it may also have stretched. Starching the bejusus out of your top and your backing before basting really does help. Good luck n keep quilting.