Hello and welcome back. Good for you for going to a doctor. It is scary but you need to be very honest, that is the only way they can help you.
I had symptoms similar to you. I was dizzy, I felt like my speech was affected. I was having mild visual hallucinations. I felt like there was a light switch attached to my brain and sometimes the switch would click off and on. Very quickly, like split seconds, but it was almost as if my brain click off and on periodically throughout the day. I'm not sure how else to describe it. I had MRIs, and EEG (to test for epilepsy) all kinds of tests. It turns out it was the alcohol. Since I have quit things are rapidly improving.
I would suggest reading the book "Under the Influence" I have ordered a copy and am waiting for it to arrive but I saw excerpts of it on a thread here. It really helped me to see that my problem with alcohol is a scientifically proven medical issue. Alcoholics process alcohol in different ways and our brains work differently than non-alcoholics.
Best of luck.