Originally Posted by cjomomma
Also clean your bobbin area.
My thought also. I would even do further and remove the plate and get all the accumulated "stuff" out. Might be worth a service call for cleaning.
Also, you might want to start with a "thread saver".
When you come to the end of a seam, run a scrap fabric through and snip your initial piece off, leaving the scrap under the needle. When you begin to sew your next piece, there will be no loose thread to get caught and create your "birds nest".
Good luck.