I am in the middle of stitching my Chesse 16, the first couple of feet went fine, but as I get closer to attaching the side panels to the bottom panels near the middle, it appears as thought they will not meet properly?. When I tried to push down the bottom panels to get them flatter, it buckled in the middle, please see photos. I have the center support in, but it seems wide than the actual bottom panels will reach? Should I take out some stitches, put in only stitches a couple of feet first, then go back. One thing I noticed is that although I loosened up the bottom stitches, they still seem to be holding tight? Any help is greatly appreciated.