It sounds like you may not want to be a nurse very much. Try wearing modest clothing, take short frequent breaks away from the books (light cardio?), and hide the mirrors.
When I was younger and had a BP of 95/60, I would often lose my vision after standing up. Stress has caused my BP to rise, so I don't experience it much now.
I have owned a Bowflex Extreme since February 2004. It has a separate set of rods for each arm. Don't know about yours, but since you say you are forced to go from 50 to 60 and you have 5 pound rods, I will assume that you are going from 25 (10 + 10 + 5) to the 30 pound for each arm.
I had...
Sounds like weak rotator cuffs. By doing the exercises on these links, I have almost eliminated the crackling: http://familydoctor.org/265.xml
A weak rotator cuff will limit shoulder strength increases.