Help with sewing machine

Two 7469's, I'm jealous! I will eventually get another machine with a bigger throat, but for now my Sally does the job (yes, I named her! lol)

When my bobbin wasn't threaded right, the stitches just pulled right out because there was only a top thread, there wasn't any bobbin thread being used at all because it wasn't run through the guide and I didn't the thread up because I was in a hurry. When you say the stitches are coming right out, are there two threads or one? If there's two, are they locking together at all? If not then that makes me think it's something going on in the bobbin area. I'm fairly new at sewing, so some of our more seasoned quilters may know exactly what the issue is :) But my guess would be to check out that bobbin, make sure it's in the right way and threaded through the little tension spring properly.