I'm so sorry this is happening to you. I just went through a month and half of nightmare quilting for different reasons but the same sinking feeling of failure. Rip it out, rest a while and then seek to find a new way to go about it. SITD is easier by hand with a better result in my personal experience. Even if you have to do it one stitch at a time, it goes pretty quickly. Perhaps you can do that in places to help hold the layers evenly when you go back to do the stitching with your machine. Also, if you aren't using one, a walking foot can help immensely when doing long rows of sewing so the fabric layers move over the feed dogs evenly instead of pulling the bottom through faster than the top layers. Best wishes!