Irregular heartbeats?

I've been having irregular heartbeats lately or that's the way it feels. My heart seems like it beats too fast and I get dizzy, sometimes I have to adjust the way I sit or stretch myself out. I'm now two weeks away from my due date and it's happened more frequently then most. I can barely talk cuz my heart just can't catch up. Can someone help..? I had to take my necklace off because I felt like I couldn't breathe.