Hi Ruby Lots of friendly support & advice on the main 52 52Thread52 to keep you on track. Also loads of info in the OP. Come join us

Some tips:
NFDs
. As explained in the OP, many overweight folk have got used to overeating, so their "normal" eating is too much on NFDs, once you have lost the initial weight.
. Use the TDEE calculator their to find how much your body burns daily and aim for this on NFDs.
. Use mfp to train yourself until you can properly judge how much to eat.
. Do NOT snack or graze, because this keeps insulin permanently raised, so you are hungrier.
Eat 2-4 proper meals. If you want a sweet treat or crisps, nuts etc have this after your main course, as your pud.
FDs
. Eat 1 teasp Marmite (10 cals) from the jar, mid-morning & mid-afternoon to avoid headaches. It replenishes salt & minerals. Also has B vits.
. Try just lean protein and veg, without any starches or fruit. This lowers insulin and can help hunger & weakness.
e.g. salmon & salad with lemon / vinegar
baked fish or grilled steak with baked or stir-fried veg
. If you like coffee & tea, keep them, just include any milk or sugar cals (I have black with sweetener, 0-cal)
Some folk have Coke Zero
. Some folk take a long time to get down to 500 cals. If you still feel weak, aim for say 700 cals first, then ease your way down.