Try using a metallica needle, or a 90/14 topstitch needle. They have a larger eye so they don't cause as much friction on the thread.
Also have the spool standing upright, lower your upper thread tension slightly, and try bypassing the last thread guide just above the needle.
Start with the needle change, and placing the thread in a upright position, and do a test. If the thread is still breaking try the tension fix and thread guide bypass.
Also, always reduce your speed when stitching with specialty threads.