Just some ideas. Try a new needle and depending on the size you have in now a larger one. Also use a top stitch needle, which has a large eye, a large groove and is a stronger needle. Make sure the thread has a clear path, sometimes a small nick on the end of the spool can hold up the thread and cause it to break when doing FMQ. Try keeping your feed dogs up, sometimes that actually works better than down.
Hope maybe one of these ideas will help. It can be frustrating until you get the hang of it.