Looks like you're on the right track. Carbs under 20g total, good. Cheese limited to 4oz, good. Lettuce, good. You might want to add some low carb veggies other than lettuce & onion. If you're not taking any vitamins/supplements, add that to get the nutrients you're missing from the veggies. It would also be good to add some regular exercise to your program, even if only 15 minutes- every little bit helps. Good luck.
God Bless,
Amy-Lynne