Frizzer, it may be worth going back to the ER or your doctor if you are concerned.
Withdrawing from alcohol caused severe anxiety, and physical symptoms such as panic attacks, and the levels of anxiety accompanying alcohol withdrawal can be truly unpleasant.
On one ocassion, a very similar experience was thinking there was not enough medication to get me through, and once the anxiety started it took hold, and continued to go up and up. Eventually, I took myself off to the hospital in a taxi. The act of going to casualty (UK equivalent of ER), talking with someone grounded, helped me calm down. In the absence of physically going somewhere, you could try an AA helpline or similar, to just talk through what you are experiencing. If you are at all concerned about your physical well being though, do go and get some face to face help.
And if it helps, you need never go through this again.