Why do I get queezy?

I have a bad habit of getting nauseous around any sort of medical equipment. I usually become light headed, queezy, and eventually faint.
This can happen while watching a movie or in real life. I had to take a CPR class and the whole time I was taking big breaths and diverting my eyes from the video we watched and the dummies we practiced on (hopefully I can keep it together if I ever have to use my CPR skills) Going to the doctor is hell for me, I usually faint when they talk about shots, I have yet to ever get an accurate blood pressure measurement. My question is. is there any time of medical reason why I get faint around medical equipment? I am not anemic, eat regular healthy meals and am hydrated.