I find when my strips and blocks don't match up to size, it is usually because I did not line up the points. Start from the center blocks and move your eyes out. If you notice any points that do not match up, maybe there is a way to rip out a few seams and fix it. Your top yellow/blue block the yellow seamed corners don't meet the two on the sides. It does help to have a small ruler and constantly measure the blocks as you sew. Measurement is off, then you may need to adjust the seams.