I've had anxiety my whole life and have always had this weird ability to always feel my heart beat. Recently I was put on a beta blocker to stop my heart from racing when I'm anxious and clonazepam for the anxiety. However, I've been feeling out of breath and like I'm not getting enough oxygen lately and when I laugh I feel very lightheaded, same as when I stand up. Could this just be anxiety? I went to the doctor a month ago and he listened to my heart and said it sounded fine