A lot of great advises here. And + karma for nerdykarim for reaching out.
I am not a lawyer, nor have I studied it, or been in your situation, so this is pretty general stuff.
In my experience, doing well on tests is all about living the field. Talk about law with your friends, think about law, dream about law. That´s how to pass, in addition to the advise the other guys have given, of course.
Whether to take the bar, or not, is a different story. Pro/con lists are great.
Pros: Stability, and ends are meeting, so the current situation may not be great, but it could be worse.
Cons: Well, you have a J.D. and you have 3 equally crappy jobs. Not the best idea.
Study for bar:
Pro/possible outcome: You pass, and get a relevant, and better paying job.
Con/possible outcome: You fail, are in more debt, and shit is getting serious money-wise.
Get a real job outside of law:
Pros: You can start looking for a job right away, and it will be better paid.
Cons: Most likely not as well paid as passing the bar and getting a good gig in law.
I recommend option 3, if things don´t work out, you won´t be knee-deep in debt and trouble. If they work out, good for you. There is often openings in sales/ customer relations in most firms, and with a J.D. you should be well-qualified.
If everything fails: http://www.marines.mil/ GLHF; I did.