I've looked at your chart and tend to think

as well. I see you have VIP membership and think it would be a good idea to ask the experts on FF what they can suggest.
I also notice you are not putting in 'night shift' or disrupted sleep pattern or anything, so I am guessing there may be a clue in the amount of sleep you are actually getting before you temp. You probably have a better idea than I do as I am only on my 3rd cycle of charting with FF, but I too work shifts, hence all the open circles on my chart.
Let us know what the experts say in the VIP post if you choose to use this option.