I feel the pressure thing, PMS on top of a divorce (including 0 child support), making sure I dont over draft my bank account every week (and sometimes failing at that!) a VERY stressful, low-paying job, a 5 year old, and diet/excercise on top of it-FORGET IT!
But how about making them eat healthier "deserts?" I dont know how old your kids are, so its hard to say how well they adapt to change, but my daughter doesn't realize that I stopped giving her Whole Milk, or that we don't eat ice cream any more at night, she has appreciated the Rainbow Sherbet that we share every once in a while, and doesn't even realize that mom doesn't make cookies/brownies/breads anymore (Oh how I miss it). You can keep FF whip cream, or maybe find some recipes for healthy cookies/breads/brownies. You can absolutely always find your way around these situations. Have faith in yourself! You CAN do it. No excuses!