First, My heart breaks for you!
You must have a bad taste in your mouth for nursing already, but better is out there. And, as long as your in the position you are in, are you doing your shift the same way everyday? Or, are you trying new things like organization, and delegation when possible? Are you trying to handle everything yourself?
You are probably surrounded by resources you didn't realize you had. Talk to your nurse manager about how you feel, and see if she/he has constructive criticism for you.
Several studies have been done about breaks in the nursing profession. They always turn out the same information: Breaks make you MORE productive, sharper thinking, less frustrated, and gives you a chance to plan and re-evaluate your daily goals. This all said, if it's just the unit you are in, and thats 95% of the problem, take a day off to job hunt.
On the working off the clock, thats just blatently against Federal Labor Laws, and this makes me Sick! You have a right to be "on the clock," and if anyone is forcing you off, they are a CRIMINAL! (Unless it is for you to go home, or end your shift work).
Slavery ended in the 19th Century (200 Years ago!), and you don't have to put up with that.
As far as supporting your parents go, I totally feel you their, my parents financial lives are in ruin, and I have always helped them out, and I know the stress that causes you. If you don't change your situation, you will definitely burn out, lose your health, and NOT be able to support anyone. Be good to yourself, and know that you deserve a fair work environment, and that we alone are the masters of our on fate. Once you have that great job, come back and help someone else on AN, I know it can happen, just take those reigns and make it. Start by sending out your resume, reading classifieds, Networking with friends, and reading about other areas of Nursing you can potentially move into.
We only live once, and you have achieved way to much to go out like this! Take a deep breath, form a plan, and act on it!
May Good Luck, Fortune, and Peace come your way.