I'm confused...are you a 4th year now or are you an intern?
If you are a 4th year now, I would suggest staying out of psych and trying to either get into an ER program this year, or 2nd choice would be doing a medicine prelim year and then trying to switch to ER later.
If your board scores and grades pretty good for an ER applicant, and you can get an LOR or two from an ER doc, I think you should be able to get yourself a spot...perhaps not this year, but next.
Assuming you are a 4th year student, I think you should go to the ER dept. @your teaching hospital and talk to the ER dept. chair and/or program director, tell them you've had a change of heart, and ask for their advice about what to do at this point in the year.
Don't do psych if that's not really what you want to do, b/c it will make you miserable. I'm sure the psych programs would rather not train someone who is going to bail after 1 year, either.