I know your heart has to beat harder to move more blood through your body while pregnant, but you can give yourself a panic attack with just a few small symptoms and a anxious mind. Take some deep breaths, try breathing into a paper bag. Whatever it takes to try and calm down. But also, dont ignore your body, if its telling you somethings wrong, ease your mind and call your dr or go to the ER.
The key word here is scared :) sounds like an anxioty attack! Try breathing into a paper bag and lay down and listen to your favorite music! Otherwise go to the ER.
I'm one day behind you and I'm having the exact same issues and I already know I suffer from anxiety issues. Unless its causing serious issues i wouldn't be concerned