Well, I'm still in FNP school, but some of your words rang true and I just wanted to offer some support and some encouragement.
I have been an RN for about 12-13 years now. I worked CCU for two years and have spent the rest of my career in cardiac rehabilitation..which I totally love. I started investigating an FNP program because I LOVE working with and managing patients with hypertension, diabetes, CAD and CHF. Since I was starting school and I knew I would need the skills (plus, the shiftwork would come in very handy with school !) I MADE myself switch to the ER.
I stayed about 1.5 years. Some days I loved it, most of the days I hated it. I realized it isn't the job or the patients, but more of my personality. I thrive on a predictable routine and the ER does not really provide that environment.
It DID, however, tremendously boost my assessment skills and introduce me to a wide variety of patient care scenarious I would have never encountered.
I am about halfway through an FNP program and almost done with my first clinical class. Can I say how much I LOVE working in primary care at a family practice clinic ? I get to sit down with the patients, take my time to do a thorough assessment and work on lifestyle and disease management INSTEAD of cleaning up poop, fighting combative hypoxic patients to put in lines and tubes and all that wonderful stuff.
From the sound of your post, the lack of predictability and the focus on skills that you do not really like doing is what is making you abhor the ER and making you question your ability to be an effective FNP.
I switched back to working in cardiac rehab and am taking just one or two classes at a time. I am glad I am in a school that allows that. You may find that is an option for you that would allow a predictable job scenario (that you don't despise) and allow you to work through school.
There are also LOTS of work at home opportunities to help you earn some extra cash. Internet based web coaching is new and emerging. Some long term care insurance companies pay RN's to go and do intial assessments for people who have applied for a policy.
I hope I haven't rambled, just wanted you to know that even though you hate the ER you CAN still thrive as an FNP student and find your niche.