Lottie, you said a lot there I could really relate to (obviously)
I know the feeling about the waiting game not sure what the future holds for our LO's. It's like everything is on hold til they get bigger, and right now I feel trapped a lot more than I'm guessing a 'normal' full term mum would with a baby. It's hard enough to get out and about but when your baby has appointments to attend and you constantly run the risk of infections etc it runs you down.
Facebook is a shitter for me too, I see mums all the time gushing in their status about how they "love being a mummy" and how "being a mummy is the best job in the world". And I often sit there and go "is it fuck!". That feeling goes away and comes back throughout the day. I have my good days and my bad days. And I'm sure these Facebook mums have just as much of a rough time of it, they just put on that front.
As for "not being able to do pregnancy right", if thats the case then I am bloody hopeless

Who said pregnancy had to last nine months?!?! Lets face it, at least we were't waddling around!
It sounds like you need to speak to someone and vent it all out. My HV sent me to a counsellor and having it out with her did help me to understand why I felt this way, and allowed me to deal with it better. I hated the idea, but I went, and I'm glad I did.
How is your HV, is she nice? You could speak to her too - they see PND and similar all the time and its sod all to be ashamed about - nobody said this was easy hun! They've been through training and know the signs! xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx