OK, I actually went on youtube (I'm an impatient person, I guess) and here's what I found out. it IS a tension issue, PLUS the actual length of the stitch. Silly me I was trying to stitch a straight stitch on a 1.5 setting with a HUGE needle through several thicknesses of really thick fabric. There just wasn't enough room to make a good stitch with such a large needle, so close together. I solved the original problem by holding the fabric REEEAAALLY tight as it was sewing, turning the stitch size to a 3 and kind of forcing the fabric to advance. I used the thick needle. BTW, the bobbin was created from the spool thread, so it was the same weight. Also I rethreaded that needle and bobbin so many times ('cause is was messing up so many times) I know I had the ends pulled out far enough and if the needle thread was twisted around the needle (I've done that before too) the needle would have snapped in two. After I changed to the red needle (and was working on a smaller area to sew ie, straps to gusset) I changed to a basting stitch and what do you know it ran across it like a rock skipping a pond. I reduced to a three length and stitched again a couple of times, and when I put in the lining I plan to run across it a few more times, for good reinforcement, still using the longer stitch.
I'd like to show you a picture of what I'm sewing but I'm on a pub acc computer right now and all my stuff is at home. it's a Butterick bag with a single strap, lined, two outside pockets on one side, side by side and an inner pocket on the lining. I tend to load my bags heavy, so the straps on this will have to be sewn on really well. I also stuff the pockets, and so I've used the heavy pellon and rather heavy (I'm not sure, but it may be upholstery fabric) fabric for the lining. It zips across the top (that will be another REALLY fun part of construction, but I think I'm up to it! If not, maybe I'll get back on here and ask for more advice. Thanks so much for your help.