Quitting a job after a short stay...

I'll try to keep this short. I work for a large system as a PRN nurse. I took a second position in the same system and have worked there a month. This second position was something I have never done before and in a short amount of time I determined it wasn't the job for me. They are undergoing huge changes in their management and the orientation that was presented to me was no longer going to be the way it was done. I tried to stick it out, but simply couldn't any longer so I quit. I sent the leadership team a heartfelt letter and placed as much of the blame on myself as possible without making myself look bad. I did mention the orientation change in the email, but just mentioned that it made things more difficult for me but that I was happy they were taking steps to improve their unit.

I've never done this before, quit a job so soon after starting. My track record is about 4 years at most of my jobs and then my reason for leaving is valid (need for more hours being the reason I quit my last position). I'm still employed with the original job in the system, however I'm interested in another position that matches my background.

Do you think my quitting the second position will affect me negatively? I've already met informally with the manager of the job I've not applied for and he's interested in me. I've also got character references who work for him that will vouch for the fact it's not in my nature to quit a job so soon after starting. Just sad the job wasn't what I thought it would be and that I had to step out of my character and leave it.
as long as you are honest with this hiring mgr (the one who has shown interest in you), i can't see this interfering with anything.however it may be different when interviewing for other positions.i can't say whether it'll make a difference or not...but since the terms of employment changed shortly after you started, to me, that is valid reason for leaving.just have any prospective mgrs focus on your first job, where you have been for awhile.that alone, should demonstrate commitment and maturity.and yes, character references should account for something.i would hope so anyways.best of luck and keep your head high.you'll be fine. leslie
Thank you very much for the shot of confidence I needed. I just am nervous since this isn't something I've done before. I plan to go with honesty as the best policy with this situation. I did hear back from the interim manager of the position I quit and she was very kind. That meant a lot to me because I truly wasn't out to do this...quit shortly after starting. I'm hoping things go well and lesson learned. I've apparently found my niche in nursing and need to focus on that and realize my limitations. Thank you again.The manager of the job I want contacted me today to let me know the position would be posted and that I should apply for it and let him know once I did. I'm very excited with this opportunity, it's what I've been doing for the past 5 years...just now with a different agency.