This happens more times than I care to admit. So frustrating. So . . . I take a breather & clean out the machine - bobbin area, presser foot area, needle area, thread track, etc. If I can see it, it gets cleaned. Even my thread stand. Sometimes, I even replace the bobbin and/or the top thread. By the time I've finished, my frustration level is a lot lower. I thread back up, take a deep breath & start again but slower. Works for me. Good luck & happy quilting.