First things first: You MUST get treatment for your depression! Nothing else in your life is going to work until you deal with this basic issue. Your employer may have an EAP (employee assistance program); ask your Human Resources people about this. It's free, confidential, and can be invaluable in helping you sort out what's eating at you.
Also, there are free clinics in almost every city or town of any size; oftentimes they will help you obtain necessary prescriptions as well as referrals for free or low-cost mental health services. In addition, a number of pharmaceutical companies have programs for people without insurance, and when all else fails, there's good old Wal-Mart, which just put in place a $4.00 maximum on some 200 of the most popular prescriptions. So, there IS help for you if you can't afford to go to your regular MD or pay for meds.
Secondly---Hospital nursing these days seems to be, more than anything, designed to separate a nurse from her sanity. I'm about as determined (OK, stubborn) as they come, but I just about lost my mind after 3 years of M/S nursing which was, as you say, more about how many directions I could be pulled in and how much stress I could take before I cracked. Well, I DID crack---basically had a nervous breakdown in my NM's office---and quit my job nine days before Christmas, without another job lined up. Scary........but do you know, I was able to draw unemployment benefits even though I'd quit, because both the physical and mental strain were so extreme that I'd had no choice.
So I took two months off to rest and figure out what I wanted to do next, and by the time I was fully recovered, the RIGHT job was out there, just waiting for me. I've been at this job since February, and I've never been happier..........for me, the perfect position is as a DON in an assisted living facility; for you it will probably be something completely different. But the take-home idea here is, PLEASE don't give up on nursing entirely---there are opportunities in many different areas which don't necessarily involve being treated like a pack animal and dealing with the less attractive aspects of humanity.
I hope this is at least a little helpful.........I hate to see nurses in the sort of position I was in, but having "lived to tell the tale", so to speak, I'm here to say that it DOESN'T have to be that way!
Please keep us posted..........a lot of us have BTDT, and we care.