Ruth Ann check the tension on top, the wheel lowers and raises your foot, I end up with loopies when I forget to put down presser foot, even though sometimes will look like it's down. If its on a frame where you reach back to hit the thread cut, found myself spinning the front tension wheel with my arm, changing the tension, have also learned some thread seems to get hooked on the bottom of the spool and has caused thread breakage.
Good Luck !!