quitting PRN job - etiquette?

[pookashellz]

kind of a continuation from my other topic, but posting it as another thread because someone else might be in the same position and searching for advice.

I'm considering quitting my PRN job. I'm currently experiencing health issues and after working my shift today it's apparent my boss and coworkers are frustrated with me going slowly, always needing to take breaks, calling out/cancelling shifts, etc. I'm thinking about resigning/quitting now so I can salvage my reputation as a decent worker, rather than continuing to get worse and either getting fired and/or getting to the point where no one would give me a positive reference.

I'm scheduled for shifts up till the end of 2015, though. I've never had a PRN job before so I'm not sure what the accepted protocol is for quitting - do you have to finish all your scheduled shifts before leaving, to avoid being blacklisted/placed on the do not hire list, even if that means you can't quit for another 3+ months?

edited to add, maybe I should/could email my boss about my concerns and see what he says?

[RN403, BSN, RN]

There should be a policy on this. The amount of notice you must give as a per diem employee should be outlined in your employee handbook or wherever they keep policies. Check with human resources if you can't find it.