I'm going insane!!!

hi everyone,
Ive been a nurse for about 4 years now and have been following this forum off and on. So far I like the paycheck and taking care of patients, but I cannot handle the stress/anxiety. I understand this is a constant issue on this forum but I just want some individual advice. I've had 4 jobs now since I got my license, so I guess I don't look very reliable or committed on paper.

My current job is homecare (been doing it for about 3 months) and my anxiety level is sky-high! I can't sleep, I can't eat, my heart pounds, I've had a headache for a few days, I'm constantly arguing with my fiance, etc etc. and bringing him down. He hates it. I hate it. I can't take a LOA because I'm the breadwinner while he finishes up school. I try to exercise as often as possible, take long warm baths, I have lavendar all over my place to calm me down, but its never enough. I'm always worried I'll do the wrong thing, say the wrong thing. I've made a few mistakes (nothing that would hurt a patient, but just silly stuff like giving a family member the wrong number to order a bed, etc). Im extra cautious, letting the doctors know more often about their pts. I feel like Im annoying my coworkers constantly asking questions. Its all the learning process what I've realised is wrong, but I CANNOT STAND the unknown. I cannot stand not knowing everything. I cannot stand the unpredictable. I love my employer and never want to leave it. But I don't like the position. Or at least its not for me. I cannot move jobs anytime soon. During the interview, my boss questioned my colorful resume. So I don't think it would be good to leave. So I guess I should give it 1-2 years until I think about changing.

Ive considered psych nursing. Actually that's why I wanted to be a nurse. When I graduated from nursing school, though, there were limited psych nursing jobs. The only jobs were per diem with 2yrs experience. So I did the med/surg route hoping to get into pysch, but i got involved in the elderly instead. :P there is a parttime psych position and per diem position available now. however, I dont know if I could handle it. any thoughts on the stress/anxiety level of psych patients? they would be medically stable, just mentally unstable which I am comfortable with. I enjoy talking and "counseling" not acutely treating and monitoring. :P

So how do people handle the anxiety of not messing up? I feel like there is so much of nursing that I just dont know!! I hate it!! I do have an appt on thursday to meet with a counselor. However, I do not believe in anti-anxiety, SSRIs, etc because 1)I hate the side effects and 2)I dont want to rely on medication to fix my "fixable" problem so seeing a MD is out of the picture. I'm very sensitive to medications and they just totally screw me up whether it be BCP or psych meds (Ive been on several different kinds).