Could My Symptoms Of Fatigue, Dizziness, And Difficulty Breathing Be Related To A Possible Right-to-left Atrial Shunt?

Hello its been about 8 months and I don t feel right. I am 46and I have been having issues with having a harder time breathing at times,fatigue, after being up for a little bit and cooking or doing normal housework I get shaking than normal I feel like I m going to pass out,dizzy sometimes. The only thing that helps is laying down. Grocery shopping is too hard and regular shopping I can t do much of anymore before I need to stop. Maybe a few stores. My cardiologist thinks I may have a right to left atrial shunt, very small, but does not think that causes any of my symptoms. It is even hard getting through the work day even though I work on the phones and am sitting all day