Wow, have logged on to find all these further lovely responses and I've had a good cry. Thank you everyone, I wish I knew you all in RL, I'd give you all a huge hug and lots of Rolos, you are so kind to take the time. I feel so self indulgent having started this, but I wanted to reply to you all. Have deposited DCs with DH and locked myself away so I can reply in peace....there you go, I'm following your advice and getting some me time!
Where to begin? Re my DCs: I was never broody, DH was more into the idea of having children.
However, and this shames me to the core, I think I had children as a competitive exercise, if that makes sense. Partly competing with my own body, after my first unexpected pregnancy resulted in a very painful and lonely miscarriage in the middle of nowhere thousands of miles from home. I wanted to prove I could carry a baby. Competing against my mother and father, I wanted to prove I could do everything differently from them. Competing against other women, I'm ashamed to say. I was always one of those, "What the fuck is so hard about having a child? Stop moaning!" types. Also, within the context of my marriage, wanting to prove I could have the perfect package, sailing out of my career into my new role of Annabel Karmel cum Martha Steward with a killer wardrobe and witty conversation for DH when he got home. I never wanted to be a lady who lunches, I wanted to be a mum and keep a house as a vocation. I wanted to do it and be proud and happy doing it. I was competing against all those women who were not going to give up their jobs. I was going to show them up. Fucking hell, that's awful, isn't it? But I think just symptomatic of my general behaviour. Turning myself into Super-SAHM was just another way of running away and reinventing myself again. Unfortunately, this time I've taken with me 3 other people this time, who don't deserve this.
Gawd, I've just realised I essentially decided I wanted to be a Stepford Wife! One of the things I've been exploring in counselling is my taking everything to extremes. I am a perfectionist and then some. I never felt good enough as a child. Nothing I ever did made my parents happy. Nothing I've ever done in my life feels like a success, I always feel as if I could/should have done things differently or better. I don't think I've ever done anything that had my heart and soul at it's core, just what my head told me was the right thing to do. I'm a people pleaser, and I have done or not done things to please other people. When "me" has prevailed and I've got fed up of being (in my perception) used, I've run away and reinvented again. I've never had the strength/guts to change the situation I've been in, I've just run from it.
Anyway, the fact that I don't get the chance to shower every day, am usually covered in vomit and bits of mashed food and live in leggings, shout like a banshee and have nothing to say at the end of the day to DH means I am very un-Stepford. I have lost the baby weight though, I don't get time to eat and I'm constantly anxious, it's a great weight loss plan 
Also, the falling in love with your baby thing. Never happened to me. I felt no love for DD until she was well over 1 y o. I am very fond indeed of DS, but I'm not sure it's love. I don't really think I understand or experience simple, no strings love. I fall in and out of love with DH constantly, I'm always looking for proof he does and evidence he does not. The nearest I get to overwhelming feelings of love for DD is when I see her in the park, desperately trying to make friends with everyone. Although, this just makes me cry and feel hugely anxious and sorry for her, and fearful she will end up like me. So I'm probably just projecting my own feelings rather than loving her.
My hour is nearly up. I could go on and on, and I really want to reply to you all individually, but I should get on. Ultimately, I am royally fucked up in the head, and this is why I should never have had children (or got married for that matter, to my DH who is a wonderful fella). Where I want to be is alone, just alone with nobody else to think about, and try to figure out who the hell I am.
I'll come back and post a bit more when I get the chance. Just thank you, thank you, thank you so much all you lovely women who have posted here, even if you think I'm a self indulgent twat, at least you are listening, and that means a great deal. Thank you for all the advice and links, I will read this all through carefully.