HI, I Am 20-year-old Female! I Was Diagnosed With Thalassemia

HI, I am 20-year-old female! I was diagnosed with Thalassemia minor a couple years ago. I compete in track and field at the collegiate level. In my short sprints I seem to have no symptoms but almost every time I sprint a 400, I either pass out or my legs completely give up. I have a hard time catching my breath and sometimes some chest pain. I'm wondering if my symptoms of Thalassemia could have increased due to the higher level of training I partake in? Or if exerting myself at such a high level like the 400 is a risk factor for me?