If you're anything like me, which your experiences lead me to believe you may be, the addition of a dual use sit pad/foot pad could work wonders.
Just putting my pack beneath my feet left them cold more often than not. Slightly chilled feet, for me, can lead to my whole body feeling cold, whether or not I really am. I cut a piece of 3/8 CCF about a foot by 10" or so...weighs right around an ounce, gets used whenever I stop for a break/meal to sit on, keeping my butt dry and warm, then when I stop for the night, it gets stuck into the bottom of my bag/quilt and keeps my feet and calves toasty warm. This in addition to my pack under my legs keeps me much warmer. For the cost of a 6 buck pad from Walmart that you can cut into any number of shapes and sizes, it might be worth a shot for you.