I agree with all the recommendations to see a doctor. I had a professional aquaintance/friend you died from a heart-attack out cross country skiing 2 years ago (at least he was doing something he loved at the time) but he had ignored warning sings of heart problems and his family history. He left a wife and 2 kids, and many friends wishing he had paid attention to the early warnings.
Don't be that person!!!!!!
We might actually miss you!

Becky