"Trophozoite and merozoite growth ruptures the host erythrocyte, leading to the release of vermicules, the infectious parasitic bodies, which rapidly spread the protozoa throughout the blood."
/en.wikipedia.org/wiki/BabesiaErythrocyte are red blood cells and their main purpose is to carry oxygen from the lungs to the rest of the body. If you have loads of erythrocyte that are dying then you will experience similar symptoms to low oxygen (air hunger, rapid heart beat, dizziness, etc). Also dead erythrocytes are recycled in the spleen, so that organ is under a lot of stress. If you don't have a spleen, then babesiosis can be deadly.
Alternatively you might want to do some heart tests, EKG, Echocardiogram, to see your valves are fine and pumping blood as needed. Bartonella infection can cause heart valve damage, which is visible on Echocardiography and can have all sorts of issues involving circulation problems. If your heart turns out fine, then maybe your dr wants to add antimalarial meds to kill babesia. Babesia testing is very unreliable, less reliable than lyme testing.