You have had a lot to deal with, I can only imagine the stress you are under. First of all relax. It sounds like you did great in school but the test anxiety has got the best of you. My advice is to get a few books, one of which is Kaplan strategies and do it cover to cover. It is short and doesnt take long. Otherwise I would set a date to retake it- say 3 months from now. And do 100 questions a day. If you have more time one day do a little extra, or vice versa if you have less. Spend one day a week reviewing areas you might lack, says Peds or Math. But otherwise only do questions.
The day before you take it, dont do any queations, get a pedi, a massage, anything to relax.
That is how I prepped and I was just an average student. You know the information, now its about the questions and how to answer. Dont waste money on a prep. You can do it yourself! Best of luck to you!!!