Currently 37 weeks + 3 days

I was in the hospital last night because when I would walk my heart rate would go up, I would be out of breath, and my chest felt full. Well they did all the scans possible and sent me home. Today again my heart is racing when I get up to go to the bathroom and I’m out of breath all the symptoms are still there. Has this happened to anyone? Should I call my doctor again? I’m so scared confused like I know the scans are good thank god but this feeling is just so weird never had anything like it.