I second what emma says, riven.
You know I have a daughter with severe dyspraxia and a small head and it affects her in so many ways. Well, you know the story, retained at stage, still not potty-trained at 5, muscle spasms, etc.
And for a long time I thought about how I drank so much vodka and Red Bull I threw up before I knew I was pregnant (wasn't even late with my period yet at the time) and then I thought maybe it was the ranitidine and that other Prilosec or whatever I had to take in third trimester after getting that ulcer in my oesophagus and having to go to hospital.
But I had a long talk with her paed about it a couple of weeks ago and whilst we'll never know what caused her condition, it's likely it's genetic because DH, his brother and their dad have such marked dyspraxia and LDs and BIL has a small head, too.
Don't let guilt eat you up!
It's equally likely your daughter's condition was caused by the birth trauma.
Conditions like insomnia can get out of control and have the potential to be negative as insomnia can cause a lot more corticosteroids to be released in teh bloodstream and elevated blood pressure, so you have to weigh up the negatives as well.
I took low dose diazepam, too, with DD2. She's not going SN like her elder sister.
I also took anti-depressants. Antenatal depression left untreated can cause low birth weight and preterm delivery. AS it is, DD2 was born 4 days before her sister, as 38+2 and weighed 8 oz. less.