I didn't check calories, but is it possible you aren't getting enough?
Perhaps your body is going into starvation mode.
It is definitely based on what you used to put into it before.
I'd cut out the daily bacon and/or the diet pop, possibly replacing the bacon with a nice, solid sausage once in a while (check ingredients, first), or tuna salad, sardines, or some other "outside the box" breakfast choices.
Use some of the salad carbs to spice up the chicken salad, adding jicima, daikon, celery, radish, watercress, sprouts, etc., to make it more interesting.
Don't be afraid of spices, as long as the mixture doesn't contain extra sugar.
Shred some cheese on your salad, rather than eating it in a block.
Make sure you take your vitamins and drink way more water than you ever thought possible.