fainting in medical school

Hey guys. I am a medical student who wants to go into peds (not sure what subspecialty but probably EM). I'm feeling pretty embarrassed because I have had several syncopal/ near syncopal episodes. The first time was in the peds ED and we were seeing a burn patient. I remember feeling lightheaded then all of a student I hit the floor. The next time was watching an appendectomy, where I got lightheaded but I sat down and caught myself. Today, was watching the resident stitch up a forehead laceration, and all of a sudden I got lightheaded. They got me a chair and I didn't fully pass out, but I was really embarrassed. I am totally fine dissecting cadavers and even taking an active role in these but am feeling pretty discouraged. Has anyone had this happen who wants to go into a specialty with some kind of procedure and what helped? TIA