Well I certainly relate.......I quit for 6 months last year. In the first 2 months I saw 4 different consultants, who found nothing much wrong with me. I had muscle cramps, numbness, pain (could be anywhere), vertigo, headaches, shortness of breath, racing heart.....and more. It didn't feel like 'just' anxiety and I didn't feel anxious when the symptoms would strike. It all eased up between 90-100 days sober. You are doing the right thing....getting the symptoms checked. For me though I think t was a combination of my body recovering from its 'adaptation' to heavy drinking compounded by anxiety that I was surely going to die.
It is horrible, but take heart it gets better.