heart palpitations sign of pregnancy?

So the past few nights when I settle into bed for the night my heart starts fluttering like crazy and lasts for a few minutes and I feel short of breath while it's happening. I looked it up and there's only one or two threads online about it as an early pregnancy symptom (apparently it's really common after 4 weeks) has anyone else experienced this and ended up being pregnant or am I showing signs of something more serious that I should get checked for?