For FMQ your top tension should be a bit on the loose side, not sloppy but a bit loose. Also, it could be that your are trying to move the fabric too fast. If you move the fabric while the needle is in the fabric it will break the needle. When FMQ with varigated threads you do need to slow down a bit.
FMQ does take a lot of practice. You just have to find that right point between your moving and machine speed. It does take time but it will come.