How are you feeling this week babs?
I think you've done really well just to post this. It's clear you need some counselling, even if it doesn't focus on food at all, as having been abused you have so much to deal with 
It must be tempting to do an extreme diet but I fervently agree with those who've said it's a bad idea. Gradual changes won't lead to massive fast weightloss but it will be much more sustainable.
I have a lot of weight to lose too. I am taking a positive approach though, and aiming simply to nourish myself and increase the proportion of good healthy whole foods.
You could make say one small change a week, so you have time to get used to the first one before you add another. For example:
Walking past the shop for an extra five minutes, then turning round and coming back via the shop. You could gradually increase the amount you walk before getting back to the shop - maybe look on google maps and plan a route round the block.
Cut down fizzy drinks to mealtimes only as a pp said - then after a whole down to once a day, and then when you aren't so hooked on them (believe me I know how addictive they are) promise yourself you will no longer have them in the house and only buy them occasionally when out (I only have coke when out for a meal now - and I REALLY enjoy it)
Switch a white carb for a wholegrain carb (like bread)
Change breakfast - I was totally hooked on sugary cereal but one day I just decided to swap to eggs instead. I love it now. Just two boiled eggs with one slice of lovely toast.
Add an extra veg at each meal - even if it's just cutting a few slices of cucumber.
Are you getting enough sleep? Tiredness leads to hunger and cravings. You could set yourself a bedtime and stick to it.
Carry a bottle of water everywhere. Before every meal or snack, drink a good glass' worth.
Get a mini exercise bike (they are basically just pedals on a little stand) and do it for five minutes a day while watching telly (gradually increase it)
Apologies for the waffle, I hope there's some things in the list that feel achievable. The thing is, IME thinking "I need to lose weight" is incredibly scary and overwhelming because it really does feel like an impossible mountain to climb doesn't it? But by breaking it down you can actually shift the focus onto much smaller, truly doable goals. I haven't weighed myself for a few months now, but I know it's coming off as I've had to buy new smaller clothes! And I'm not really thinking "I need to lose weight" anymore - all I am thinking of is one tiny change, like those in my list above, at a time.
Hugs. You CAN do this.