You've been told repeatedly by a lot of posters (including me) on here that they have drunk heavily in the early weeks of pregnancy and their babies have been fine. You reply to each post with 'yes, but'.
I could tell you about at least three friends of mine who dabbled in Class 'A's before they got their bfp (not addicts, just social users), all of their now teenage kids are absolutely fine as well. Life happens. Very few people live a pure, organic, booze/drug/pollution/plastic free lifestyle for three months before even trying to get pregnant, it doesn't mean that all of their children are doomed, if it did, the human race would die out.
You've also been presented with the basic biological fact that the foetus, or rather the clump of cells as it is at that point, does not share a blood supply with you.
As you are no doubt aware, you can have an abortion if two doctors agree that it would be injurious to the mother's health to continue with the pregancy, that also means mental health. At the moment, because you are in the grips of a anxiety crisis, they may agree that you can have one.
I think you will bitterly regret it though. Sort out some counselling pronto and try and get this in perspective. Stop googling as well.