Welcome to SR, glad to hear you have made the decision to quit...you will not regret it! As others have mentioned, we can’t give medical advice here so it would be best for you to follow up with your doctor or the A&E folks if you still have concerns. If you were honest with them about your drinking habits and they discharged you I would assume they felt it was safe to do so, but you can always get a second opinion.
On the note of reducing or tapering, it is extremely difficult and rarely successful as it is also an attempt at controlling your drinking...which most of us cannot do, And at some point you still have to cut row to zero. Have you considered a supervised detox or inpatient rehab by chance?