In highschool whenever a guest speaker would talk to the class about illnesses, for example doing drugs and the effects it has on the inside of your body I feel like i have to throw up, also everything around me gets very dark and i get very dizzy, borderline fainting. These guest speaker seminars usually last about 40 minutes and I get sick as the presentation progresses. If it was a short presentation like 10 minutes I think I would be fine. This happened to me every time I had a guest speaker throughout highschool on topics like human illness/diseases, which has been roughly 4 times. It also happened to me a couple months ago when my optometrist was explaining to me about cells in my eyes and how I can potentially develop an ulser. That conversation lasted about 10 minutes and i felt the same effect.Besides those occurrences my health is 100% fine and have never had that feeling before. I am wondering if this is normal.