I disagree with some of the posts saying you should stay..you are fairly new as an RN but you are NOT new to nursing or healthcare. You sound mature and thoughtful..if the job doesn't fit you it doesn't fit. Sometimes the excitement/fantasy we have about a job and the reality are not even close. ANY job that you makes you physically, mentally, emotionally or Spiritually ill on a chronic basis (not just a bad day here or there) is not one to stay in when there are other options. A job you have to take medication or go to counseling for (when it's only the job creating the discord) is also one I would not stay in.
I worked in a hospital setting for years, left for about 4 years and returned earlier this year...I realized quickly, that like you, I could provide great care, deal with coworkers/physicians, etc. but feeling like you do is exactly how I felt and I realized that I, as well as the hospital setting, has changed. I shifted to PRN and will be leaving completely for another position outside the hospital setting in a few weeks. Part of me felt badly, like a failure in some way but the fact is, the failure would be staying in an environment that just doesn't work. I also realized I am the one getting up, going to this job that is not a good fit, that I really don't want to be in the hospital setting any longer and I don't have to explain it to anyone. This was a "biggie" for me.
My leaving will also open a position for some other nurse who may be feeling the same way where ever he/she is working and allow someone else to change their situation. My unsolicited advice is if you can change to another unit, do it now. Yes, there is stress is all areas of hospital nursing but there are more controlled units than the ED and yes, a patient can code anywhere, but the likelihood is less on some units.
Life/time are too short - the "golden" year rule doesn't really apply in your case since it sounds like you have to stay with the employer for a few years. Look into outpatient surgery or something similar, but whatever you do, don't keep going down an emotional and physical hole because of some invisible year mark. Take care of yourself.