It does take time to get in the groove of LA quilting. 5 hours is NOT BAD for your first attempt. I took me a 1/2 to load my first quilt. I recently did a twin size (lots of quilting with even more stops and starts in the pattern). It took me over a week to quilt.
For the thread breaking - what thread are you using in the top and bobbin? Make sure the height of the quilt is not too high or low. Not sure what machine you have, but as my quilt gets past the middle, I need to raise the bars so it's not dragging. How about needles - what are you using? Are you cleaning the bobbin area as you change out the bobbins - you'd be surprised how much lint accumulates in a short time. I also change the needle quite often. And, don't go too fast.