Messed up heart rate?

Hello ladies, 
7 weeks preggers here! 
Since I became pregnant I've limited my sugar intake and totally cut out caffeine. So tonight myself and my SO got a treat from the take away and I had half a can of fizzy drink (club orange) with my meal as the sugar intake in one can was 45% so I was not drinking it all- since I had it my heart rate is bouncing out of my chest! No chest discomfort or shortness of breathe just a crazy heart rate? 
Any ideas what this could be? Could it be the sugar and fatty food? FTM here so any Help will be great and help me relax! Thank you x👶🏼💕