Hi. If it's helpful to you, I would like to that your symptoms do sound very similar to what I experienced in July. This was before I saw my therapist and before I knew about this web site. I was so relieved to know that all of those symptoms can be brought on by anxiety.I know that it is an absolutely terrible way to feel.
When I used to feel similarly, I found a music channel that played very relaxing music. I would sit and listen to that music and try to focus on my breathing. You can search these forums or in the tool box for box breathing and for PMR. I think that both of those things can help. I remember that thinking only about the present was helpful. I chose not to think about the future - because that is where my worries existed - my panic was regarding things that might happen.
Do you remember the anxious thought worksheets? If possible, now might be a good time to examine and challenge your anxious thoughts. It sounds like you have evidence that shows you are healthy (which is great!). Use that as evidence against the anxious thoughts that you are having.
One last thing that my therapist told me. As horrible as anxiety feels, we should remember that panic attacks are not going to kill us. They are very annoying and harmless. He likened them to the hiccups - symptoms that go away eventually.
I am so sorry that you had this experience. Do you have a friend or family member that you can call? I know that isn't always the case (I had attacks in the middle of the night) but hopefully you can find a good resource. I was surprised to learn how many of my friends had experience with anxiety!
Finally, I don't think it would hurt to call your doctor's office (if you have one) to ask questions about what you can and cannot take if the above CBT doesn't help.
Take care - I will be thinking of you and wishing you well.