Sleepless, this is such a tough time and all of this is so new, it is all a bit of a rollercoaster at the moment as your mind is still trying hard to convince you this alcohol consumption is a problem. This is the key to OCD. So your fear that the baby is unsafe or that you have harmed your baby and you are unworthy of a happy outcome is the obsession and your desire to seek reassurance that you haven't is the compulsion that arises because this feels so bad.
What happens is OCD with reassurance seeking is that your mind, like all minds being a problem solving machine, is generating ways of making the horrible feeling of uncertainty and what it means in the context of this pregnancy (that you can't have a happy outcome, that you are unworthy of a happy outcome or won't be able to survive a sad one) go away. So you feel this huge urge to seek certainty and reassurance that you haven't harmed your baby by drinking.
The thing is that your real problem is emotional, even though your mind is fixating on the drinking issue. And though the mind is really good at solving problems in the real world, it really is crap at fixing emotions. So it is fighting a battle it isn't equipped to win. It tells you seeking reassurance will make you feel better, but actually, you end up feeling worse.
So it goes like this:
Feel terrible, uncertain.
Seek reassurance to stop the terrible feeling by asking people online to reassure you or consulting with medical professionals again and again about the same fear.
Get reassurance.
Feel better for a second sometimes, reinforcing the idea that the problem is the specifics of your fear e.g. related to drinking for you
Feeling terrible still there
Mind ramps it up: okay, so that obviously wasn't enough reassurance to make you feel better, let's look for more.. or in your case also, look this is obviously not working, you just need to end this pregnancy to feel better.
The mind is just not qualified to make you feel better so it's a bit like an unqualified person doing surgery. It can pick up the tools for solving the problem by asking you to seek help, but it's applying them to the wrong issue. You need help with worry and with your 'I'm not good enough to keep a baby safe and live a happy life' story. The obsession about alcohol consumption is just smoke and mirrors.
And we all have an I'm not good enough story, so you are not some freak for having it. You are clearly just desperate to have a baby and terrified it's not going to happen. This makes you absolutely caring and loving but just in great pain, which is understandable when you've been facing the threat of infertility.
OCD like thinking (whether you get this diagnosis or not, as obsessional thinking is part of many patterns of human distress) is born of stress and the structure of the human mind and how we respond to prolonged stress and fear over a period of time and can be triggered in many women by hormones. Many women with OCD will have their first episode in pregnancy.
Obsessional thinking always hits the things that matter the most. It is poured from the same vessel as your love for and desire for a happy life with a healthy child. Your mind just doesn't know how to make you feel better and you need a little help which you are going to get.
Thinking of you xx