Ummm I have a Fainter on my Hands... WTF?!

I was treated to a little tantrum that quickly turned scary a couple of days ago and learned that my daughter is a fainter. Apparently, it's a fairly common thing for toddlers to hold their breath until they pass out either on purpose or while crying as part of a tantrum. Annnnnd apparently my kid is one of those toddlers. Yesterday marked the 3rd time that Isla has done this and it is SO scary! She screams either after she has fallen and gotten hurt OR when she's angry and throwing a tantrum. It then turns into her eyes rolling back and then she usually collapses into my arms. She pops her head up about 5 seconds later as if nothing ever happened and wants to go on her merry way. After speaking with my doctor, for now it seems I have nothing to worry about because it's a pretty common thing. I'm going to keep my eyes open for any weird things like throwing up or turning blue. So yeah.... one more thing to worry about.