I get like that quite often. The heart flutters and all. Usually for me it's my anxiety. Try deep breathing. In through the nose out through the mouth. That usually helps me. Hope you are feeling better.
I also am hypglycemic. When i get to feeling that way the first thing i do is grab a snack. If that doesnt help i check my blood pressure. For me its usually one of the two. If you have recently started a new medication that could cause this type of reaction.