SAT problems?

I'm beginning to get very worried. I am currently a high school junior with high aspirations. I want to be a physicist, and go to schools like MIT, standford, cornell, caltech, etc. etc. etc. I'm currently enrolled in the Princeton Review course, and let's just say it's not going well. I haven't even broken 2000 on any of my practice tests, and the actual test is in TWO WEEKS. It seems every time I take the SAT, I am unable to answer the questions, do math correctly or even write a decent essay. I want a score around a 2200-2300, but as of now it doesn't even seem likely I'll even make it to 2000. I'm enrolled in the March 1st test, and I'm deftly afraid I wont make it. To put things in perspective, I'm generally an A, A+ student in school. I usually get As in math and almost always A+'s in physical science courses (AP Chem, Physics, etc.). My dreams of becoming a physicist will be destroyed if i can't master this stupid test. This is kind of important. Will someone please help?