For me, that means that my bobbin is wonky. If I take it out and replace it, it usually corrects the problem.

Make sure your presser foot is up when you re thread the machine.. I have had the same problem..Frustrating !!!!!

Are you going too fast?

I think you should re-thread completely. I would also put on a fresh needle, just in case. Please post the problem when you get it resolved.

Good luck!

It looks like the top thread tension is off. Sometimes one accidently bumps something without realizing it.

Looks like a tension problem. When I've had this, it's been either the bobbin thread not running through its little groove on the bobbin case, or the machine thread not threaded properly. (On my machine the tension dial is hidden inside a hatch, so I can't really change it accidentally - but maybe check that one first to be sure it's still at the right setting.) So I'd agree, rethread and test on a scrap or practice sandwich.

Good luck! Quilt is looking beautiful already.

I have done this when my presser foot was not down and also have done it when i had a bobbin issue, changed out my bobbin and all was fine.

I had very similair problem, I rethreaded, tightened, loosened the upper tension, changed the needle, did everything I could think of. Spent a couple hours and lots of thread practicing again and again. And it turned out to be that darn little screw on the bobbin. (bobbin tension to loose). Try that. But I completely understand your frustration.

Make sure pressure foot is down!

Your top thread is being pulled to the bottom. So either you don't have enough tension on the top, or too much on the bottom. Most likely is that the top is not threaded through the tension discs properly, or slipped out.
Agree, rethread the machine, top and bottom, make sure the pressure foot is UP when you rethread, and test on a scrap.
If it persists, try a new bobbin, you may have a "bad" one.