I think everyone who free motion quilts can identify with your story! Starting out learning FMQing is HARD, but with your determination, you'll get it right eventually.
Everyone here is giving you good advice for sure, and from your story it sounds like you'll need to get that tension issue resolved before you try anything else. It does sound to me like you may have forgotten to lower your presser foot. Once in awhile, I'll forget to lower mine and it will cause the same problem. Now, mind you, I KNOW I'm supposed to lower it, sometimes I just forget, and because of the way the FMQ foot works, you can't really tell by looking at it that you haven't lowered the foot.
If that's not the problem, it may be that you need to adjust the tension on your bobbin. For my machine, the way I test the bobbin tension is to put a full bobbin in the case and run the thread through it so that it is ready to go into the machine, but instead of putting it in, I then hold it up in the air by the thread. The weight of the bobbin case and the full bobbin should almost make the bobbin case drop, unwinding the thread as it goes. If it won't drop at all when I jiggle it a little bit, I loosen the tension screw, if it slides right down, I tighten it just a bit.
Once the bobbin tension is right, then I adjust the upper tension. To get it "in the ball park" I use 2 layers of fabric and stitch over it with my regular presser foot. Then I change to my FMQ foot and drop the feed dogs. Changing the foot and dropping the feed dogs does NOT change the tension, so you should still be close at this point. Then I try stitching a fairly straight line on a small "test" quilt sandwich of similar fabric and the same batting as my quilt. I usually need to make minor adjustments to the top tension at this point to get the stitches balanced in the quilt sandwich. I test it a few more times, just doing a fairly straight line of stitching each time. It's less complicated than trying to worry about quilting any kind of pattern at this point, and it's easier to see if your stitches are balanced. When the stitching seems balanced, I try out the design I'm wanting to quilt (still on my test piece), to get a feel for what I want to quilt. After all that is satisfactory, I get the actual sandwich that I want to quilt, take a deep breath (and maybe a couple of sips from the previously recommended glass of wine), and go for it!
So, to summarize:
1. Be SURE you are lowering the presser foot.
2. Make sure your bobbin tension is OK before trying to adjust your upper tension.
3. Balance your tension with a regular foot and straight stitch first, them move to the FMQ foot and your test quilt sandwich to fine tune it.
4. Don't try complicated designs at first, just do lines and curves to get a feel for it.
5. A LITTLE wine does help! And if the FMQing isn't going well, just pour another glass and sit in front of the machine and look at it, and become one with it! If you drink enough wine, you will not care if you are actually sewing or not. (But don't try to sew if you have too much wine... things can get out of control quickly...)
I hope this all makes sense, and that you get through the initial startup woes of FMQ, because it WILL be FUN once you get the hang of it. Just don't expect too much too soon. I'm usually a pretty "quick study" and it took me months of practice on and off before I was ready to quilt on anything "good". Now, a couple of years later, I'm doing queen sized quilts and having good results and lot of fun doing it.
I'm sure we'd all love to hear how your journey in FMQing goes, so please keep us posted!
Wendy
P.S. If you are located near anyone on this board (including me) I'm sure a little one-on-one time with someone who is doing FMQing would be helpful.