Hi, April ...
I have been in the place you are in ... it is difficult not to get discouraged ...
I have a basic older Brother machine, I do have a walking foot and use it a lot as it is a help with moving the quilt layers, but I sometimes do not change the from the quilting foot and it has worked okay.
It is a big step from a lap quilt to a bed sized quilt. You have the bulk to deal with. This gave me some trouble at first.
Here are some of the things I learned as I went along:
Are you using safety pins. Using large safety pins rather than straight pins helps you from getting those sharp points.
Another method is using that spray basting spray. This can be a bit smelly and sticky ... spray it in a ventilated area on the BACK of your quilt top and the stickyness extending beyond the fabric onto the batting ... you may want to wash the quilt before using it ...
That said I do not really use the spray much ... I tried it and did not really like it all that much ... but it did help when I was "learning" ... I also tried the "iron on" type of batting ... it is a bit too stiff for my liking ... you may find you like these, though.
Look into different kinds of batting.
What I do use on most of my bed quilts is Warm and Natural 100% cotton batting ... available from Jo-Ann Fabrics ... I use coupons a lot ... I really like this ... it is light, warm, it breathes and it is nice to work with. It is not bulky. It rolls up nicely to fit thorugh the relatively small space between my needle and my housing. The fabric sticks to it just enough that even on bed size quilts ... as long as I make sure everything is perfectly FLAT and SMOOTH to the edges ... that I do not need to use a lot of pins and I do not get wrinkles on the back.
I take the quilt out of the machine and smooth and re-roll it a lot. It takes a bit of time, but I can see how it is coming along and things flow more smoothly in the end.
When I wash the quilt ... (I do not usually wash fabrics before I sew)... this does shrink and puff up a bit, but it does not shift. It gets a crinkly, old-fashioned quilt look to it that I really like.
Meg has made some very good points about thread, needle and tension. I find my machine really prefers Gutterman 100% polyester thread for quilting. (Also available from J0-Ann's.) I would rather use cotton thread, but my machine does not.
Are you straight stitching? Or trying to do free-motion? Straight cross-hatching or in-the-ditch it easiest on large quilts when you are still learning.
I know you are miserable with your efforts right now. Try not to give up. I have been there ... knowing I have to rip out what I have quilted and start over ... but that is what you are going to be doing. It is just a part of quilting.
Like Jenell said ... give it a day or two ... and go back ...
You will be quilting queen size quilts before you know it ...


Pat
"Life is not measured by the number of breaths we take, but by the moments that take our breath away."... from "The Paradox of Our Age" by Dr. Bob Moorehead