I am new here and will post an intro but I hope it is ok to just jump in. This happened to me at the dentist. It felt like an awful panic attack. I was fine one minute and then after he gave me the injection I felt like I was going to die. Turns out it is one of the medications in the injection. They add epinephrine to the shot to make it numb longer and to slow the bleeding. I talked to the dentist about it and now I do not get the shot that has that mixed in. It was a really terrible feeling when it happened.