Couple of points, folks…
About fasting whilst bfing: There are at least a dozen mothers on the main 5:2 threads that I've seen bfing successfully whilst fasting. Dr Mosley says not to, but, IMO, that's just to cover his back.
ElBombero, if you go onto the main thread there will be loads of help and advice, I'm sure.
About WW: I'm a gold card holder of many years standing, and I was given a goal of 10.10. When I started 5:2ing I began to lose weight without even trying, and, over the next 8 months I lost 22lbs - so I now hover between 9.1 and 9.4, depending on where I am in the week (I maintain on 6:1).
I'm as fit as I've ever been, have loads of surplus energy and don't ever intend to let a week go by without fasting.
My point is that WW had me permanently 20odd pounds overweight for over 20 years! They tell me my allowance is 2500 calories a day (I'm a bloke), but I know if I eat that much, I'll gain weight. It's the same for women, you're allowed 2000 calories, but I don't know anyone over on the main threads whose TDEE is as much as that. Most of them are on between 1600-1800 cal.
Oh, one last thing - I've never eaten so many cakes, biscuits, treats, etc, as I have over the last 18 months - whilst still losing/maintaining weight. 5:2 works because you are never deprived - you can always have 'it' tomorrow! 
If you'd like to read further about fasting plus some low-cal recipes (and bread
), have a look at blog where I ramble about these things!