Hello! My name is Brian. I have the same experience as you, but I would like to just let you know on why this phenomena happens.
So I was addicted to Cigarettes and Pornography. Its different from alcohol addiction but similar in a way, i only say that because my addiction is derived from the same reason why people become alcoholics, which is dopamine deficiency.
When you drink, smoke, or binge on anything for a long period of time, chemical receptors in your brain called dopamine receptors lowers to create a new balance within your body, because you were getting excess dopamine by binge drinking. Drinking can increase dopamine by 150-200% and if you do that often, your body will try to adjust to it and make less dopamine receptors. This is why when you quit, you go through anxiety and panic, because you suddenly dont have enough dopamine in your brain anymore.
The reason why i mentioned this is because it is crucial to explaining why you get panic in the morning after a day of drinking. This happens to me too. So a healthy individual, with a normal amount of dopamine, lets say he drinks with the buddies for the night, his dopamine will increase to more than normal level when he drinks, then comes down to slightly below normal in the morning, (feeling groggy, tired) then bounce back to normal. However, a person with dopamine deficiency (which is ur case cuz ur going through withdrawal) will drink, his/her dopamine level would come back to near normal levels, then end up crashing in the morning to abnormally low levels of dopamine, which creates intense panic and anxiety. This disappears as you abstain from drinking and your dopamine levels start to come back to normal. As you overcome withdrawal, which may take months to years, eventually your dopamine levels will come back to normal levels and you wont experience this strange phenomenon anymore.
Hope ive been helpful, sorry for the long post. Best of luck to you.