Contraction feeling with racing heart

Anyone else have a tightening of the belly (I think a braxton hicks) but accompanied by a racing heart. I've told my dr about it and she's not concerned since it goes away and doesn't affect me one its gone. But it seems unsettling...I'm worried once I'm having real contractions back to back, my heart will continuously race. Haven't been able to find anything on this...am I the only one?