Heart concerns (any nurses out there?)

Heather
Why do I always seem to get health concerns when the doctors office is closed?
So... My heart has been fluttering and then sometimes pounding, like it's working really hard. I was worried about high blood pressure, so I went to the grocery store and did one of those blood pressure machines. It actually said my BP was 86/64!!! I have always had low BP, even before pregnancy, but this just seems really low. The machine said it was normal, and I don't have any other symptoms like dizziness or shortness of breath. I'm fatigued, but that's how I've felt all during this pregnancy. 
 
Has anyone else experienced any of these symptoms? I need to know I'm not alone... Or else, tell me whether I need to go to the ER.