You've had a number of life changes in a short period of time - it's to be expected that your stress level is very high.
I graduated in spring '05 and went straight to a Level I ER. I was blessed with an excellent preceptor with whom I was well matched, an active nurse educator and a structured 4-month orientation program. But it was still not an easy transition, from student nurse with clinicals at a few suburban hospitals to nurse in an urban trauma center. More than once I asked myself, "what have I done, taking this job??"
It took months to get comfortable with the sicker patients. I'm still finding my comfort level with trauma patients. According to my mentors, this is about the expected pace in the ER: a basic comfort level after 1 year, "fully competent" in 2-3 years.
You have the added stress of being in a new area, so both home & work might feel a little out of control right now.
See if you can separate the two for a moment, and think about how you feel about working in the ER? Do you like the variety of patients? Do you basically like the hospital? Are you getting fairly positive feedback from your preceptor(s) and coworkers? If so, you might want to give it more time.
Sending good thoughts your way ...