Working contingent

I have been working full-time in the ER for the past six months or so. I already feel burnt-out in nursing and this is already my second job after being a nurse for less than a year. I really want to switch my status from full-time to contingent, but I got out of orientation only about 7 weeks ago and I'm not sure how this would go over with my manager. Has anyone ever switched from full-time to part-time or contingent after being at a job (especially in a specialty area like the ER) for a short period of time? I'm reluctant to talk to my manager about this because they spent so much time and money training me. Any advice on how to approach this with my manager?

As far as nursing jobs go, my job is not all that bad. To be completely honest though, I don't enjoy working as a staff nurse. I don't like working weekends, holidays, odd hours, and 12-hour shifts. I wish I would have considered this before choosing nursing as a career, but I was 18 years-old and didn't know a thing about nursing or health care. I'm going back to school for FNP in the fall. In the meantime, I want to reduce my hours and hopefully some stress! I don't need the benefits or the money of being full-time.