I've read some of your previous posts and your experiences resonate so much with me. DD (now 7) was planned, but conception happened a lot faster than expected. My lifestyle was pretty bad at the time - lots of drinking, smoking, late nights etc and a very stressful job too. I've always been prone to worrying and anxiety, and had been prescribed antidepressant medication in the past for two periods of depression, but this was something else. I was obsessed with the possibility that I'd harmed my baby by drinking / smoking prior to knowing I was pg, endlessly researching online and being sent into a tailspin by a throwaway comment or BBC article. I was tearful, irritable and no amount of reassurance would be enough. Like you mention up thread, I would generate a 'reason' why the positive outcomes couldn't apply to me, and the cycle would continue. There's something v compulsive about the anxiety, imo, which means the reassurance almost feeds it, iykwim? The anxiety didn't dissipate after dd was born, although did get better, but I found myself obsessing over milk intake and SIDS in similar ways. I eventually sought treatment when dd was about 5m old, with SSRIs, and then never looked back. DD is the light of my life and entirely happy and healthy. Whilst she's showing some signs of being a bit of a worrier, I think that's likely to be a personality trait or learned behaviour tbh, and is not uncommon in children with all sorts of starts in life. There's lots of mh issues in my family.
With DS, who's a toddler, I took proactive steps early on in the pregnancy. Engaged with perinatal mh team, had some cbt, worked out a plan for after he was born - in my case, imipramine so I could bf. (In both my pregnancies I was too scared to take meds although was reassured about them by GP and psychiatrist - part of the anxiety I think). Imipramine worked well, although have swapped to Citalopram since I stopped bf-ing as wasn't keen on the side effects (dry mouth etc). Pregnancy with DS was better: still issues but had more understanding of the mechanisms at play, if that makes sense? DS is a monkey, but also the light of my life and happy and healthy too.
You can do this, and there is light at the end of the tunnel. Wishing you all the best xxxxx