Ah, op. I've read the whole thread and yanbu. My baby is 8mo and I weigh EXACTLY what I did 2 weeks after giving birth! I know exactly what the problem is - too much cake, lots and lots of gentle walking (for hours each day) but no strenuous exercise.
I hate bring fat. Yes, the f word. But I am - I wore 29 inch jeans pre pregnancy and now... I wear my stretchy maternity jeans!
I feel crap about it and have started to ring the changes. Once I set my mind to it I know I'll loose the weight and I want to be back to normal by Christmas. I think I'll do it 
So I hear you op! Most of my Mum friends lost the (little) weight they gained very quickly. None of them have made me feel bad. They're all encouraging and great. But I feel the pressure from other friends and some family. And yes, from society too. And it's quite painful isn't it?!
Yanbu but I can see why some posters have felt you're being a bit defensive. There are always more things we can do, but it sounds like it's your Mum you're really cross with/ hurt by.
Next time I'm pregnant, I will eat what I like but not go crazy. I've learned my lesson - thought all the weight would miraculously fall off when my baby was born for some reason.
For those who've posted expressing concern about the burden that obese people are to the nhs - yep, I agree. But the op isn't exactly enormous at 8kg overweight. I'm 3 stone overweight, but you'd be preaching to the converted if you told me. I'm a doctor!
But for the few who've been horribly judgey about the op being a bit overweight - in the nicest possible way, sod off. As I havd said, the majority of my Mum friends list any extra weight very fast. None of them are passive aggresively mean about the fact that I'm still chubby.
Be kind to fellow Mums!
Epic post. Sorry!