This is something many of my clients have struggled with as well (I know I did!).
They stop drinking... but then their emotions start going haywire, insomnia, headaches, nausea and other symptoms. Then there's the overthinking and sense of panic to get out of their current state of mind.
The first thing you want to do is see your doc. Your safety is #1 and it's good to get full checks to make sure you're ok (heavy drinkers are most at risk of seizures which can be deadly).
Alternatively, one thing that worked for me (IMPORTANT: I'm very mindful about recommending it as everyone is different so use at your own risk) and that is deciding you're just not going to get any symptoms. From doing that (and the other work) I didn't get any symptoms.
When you decide that you're just not going to get symptoms, it doesn't mean they won't show up... it just means that you're not going to pay them any attention... which diminishes their effect because you're not focusing on them.
And while you do that, you can use this meditation to help you stay grounded and balance your emotions out.