::WARNING - I'm going to describe some wounds and situations in my response, to accurately portray my experience... scroll past to the final paragraph if this will upset you::
So, I had the same fears when I left my first career (teaching), and decided to try a position in the medical field. I applied to a CNA program, and started volunteering at my local Humane society on spay/neuter days....partially, because I love animals and wanted to volunteer some time, partly because I wanted to test my response around blood. My first day, I got to watch a vet do a cherry-eye correction (stitching around an eye, yikes!). I loved it though - something about seeing the blood, but KNOWING that there were more experienced people around me who knew how to help and improve the animal's life was really reassuring.
Fast forward- As a student nurse, I got to observe two full knee replacements on my OR rotation. Again, it's gristly, but so reassuring to see professionals improving lives. It's amazing what we can do though surgery nowadays! Watching a surgical wound debridement was more....troubling to me, more messy to watch. But still, knowing that it's necessary and needed is a BIG mental thing. I also had some gnarly wounds I saw as a med/surg floor CNA - including one abdominal surgery dehiscence. That patient was fine...there were some stories that did not have happy outcomes, but knowing that I was part of a team that did their best and provided care to these people was very important to me: we can only do our best.
Fast forward again, student nurse ER rotation - at this point, most of my bloody experiences have been in surgery or wounds that have already been cleaned nicely and bandaged. That day, a man came in who had been hit by a car: the car had been going slow, but had backed into him, pinning him against his own car. His calf was gashed open from ankle to knee, and you could see the bone. The surly male ER nurse I was following shoved the dressing kit to me, then me to the patient! I felt this rush - It was MY TURN to directly help someone in pain and danger. I loved it, and I honestly cant even remember seeing the blood itself - I just went into the zone when I was cleaning the wound and preparing the dressing, analyzing how much I would need and the best way to apply it etc.
I never would have thought I'd be someone who thrived on the "blood, organ, some cruel things"....but someone needs to do it, and I found that I can. I'd like to specialize in wound care or Hospice, someday. Seeing blood in the hospital is still very different for me, than seeing blood outside of the hospital, where there is no one to turn to if things get serious. In the hospital, I feel supported. Go slow, get exposure though a CNA program (where you will be dealing with stable patients) or though a volunteer vet tech position if one is available (your local humane society may do surgery days locally and have volunteer positions). You might find, like me, that seeing blood in a medical setting is very different from seeing it in "the outside world".