My stitches are usually not a problem, but one time I had lint in the arm of the bobbin case. I used to use a pin or needle to try to clean it out, but now keep a small dental floss...and floss my bobbin case! Keep at it....could be you are learning to trouble shoot for another time. Big deep breath...keep a list of what you have tried. Do you belong to an owners group for your machine? Other owners are the BEST resource.