Hi Holly and welcome from me too. Your experience also sounds similar to mine. After I had DD I was such a mess, even when she started sleeping better I found I just could not sleep at all. It was like I was on permanent "high alert".
Initially I didn't have anxiety about insomnia, but as the weeks went by my anxiety about not sleeping got worse and worse. Eventually I got to the point where I would lie awake the whole night and not get a wink of sleep.
It is very isolating when no one understands - people just seem to think that if you get tired enough, you will sleep. For me, it seemed the opposite was true - the more tired I got, the more frantic I got and the less I could sleep. It was like a vicious cycle. I was ready to punch anyone who suggested lavendar oil.
I was given zopiclone (a sleeping pill) which helped the frst night, but pretty soon afterwards they didn't help any more and because they were addictive I was terrified of taking them. I was also given citalopram (an AD) which I held off taking but eventually gave in and started. It made me so much worse - anxiety, shaking, terror really. I stopped it after 3 days because it was so awful.
After that point I became so ill that I was eventually admitted to a mother and baby unit. Eventually I was given a different kind of AD - a sedating one - called mirtazapine. It absolutely worked wonders for me. Helped me sleep and calmed my anxiety a great deal. I am off it now, but I really think the mirtazapine helped me turn the corner.
Like becky I still have bad nights occasionally but on this thread I have found such good support to get through the bad days that follow the bad nights. We have found lots of coping strategies to deal with the insomnia and minimise the anxiety. We like to tell each other "Positive Sleep Thoughts" (PSTs) which are things to help you stop thinking so negatively about going to bed and trying to sleep.
I hope this helps, please feel free to keep posting, we have all been there and no how hideous it is xxx