I worked though all 3 of my pregnancies, universal percautions obviously still apply. As for HIV proph for exposure, speak to the infection control nurse at your local health dept or at your school, that would be a good place to start.
Another consideration is insurance, if you don't have it through you hubby/signif other, you will probably have to wait through the 90 day probationary period. The pre-existing cond doesn't appy w/ pregnacy but the prenatal care is essential as you already know.
These are the only problems I experienced.
1. My annual PPD was waived because there is no data to its' potential effect on the fetus one way or the other.
2. I barfed in a patients room because of a smell that didn't sit well. (it was the lunch!)
3. Had to be much more careful taking care of confused patients, got kicked in the stomach by a 50 yo ETOH'er going through withdrawls. (baby was fine, but it was terrifing)
Good luck. Keep in mind that you will be working in a profession that is predominantly female and many will understand your fears and work with you to keep you and baby safe! And of course the men will as well!