Hi Millie, what you have described is very much what began my panic attacks. I had a year long struggle with bad health and became so afraid of the illnesses returning that I brought on panic attacks whenever I felt the lightest tingle or thump in my body! With the help of a great CBT coach/psychologist we began uncovering the triggers for my anxiety/panic, which were always physical sensations followed by a rush of axious thoughts and then a panic attack. We then began the process of exposing myself to the physical symptoms in a contolled environment (see session 9 of the program) in order to retrain my brain to recognize that these can be just physical sesations and not life threatening. This really works. It builds confidence in your abillity to deal with unpleasant sensations and identify your anxious thougths. Once you can do this and understand how it feeds the panic cycle, you gain control. I'm extremely grateful to say, I have not had a panic attack for several weeks now and the last one I had was mild compared to what I had experienced in the past.
You may also find this book helpful, which was recommended to me by my CBT coach:
It's Not All in Your Head by Gordon J. G. Asmundson, PhD, and Steven Taylor, PhD.
I hope this is helpful. Trust yourself and keep reminding yourself that you are an intellegent, strong person who can overcome this and beleive me, ou will! :)