1L: Should I stay in law school or switch over to a Masters degree (already accepted, can start in January)? Advice?

I am a 1L at a Tier 2 law school. I majored in environmental science undergrad and applied to a variety of law schools, grad schools, and fellowship programs my senior year. Decided to pursue a joint degree program and get my JD/MS Environmental Science. Had a LOT of doubt about entering law school, mainly applied because it was "my goal" and I was unsure as to whether I wanted to go into scientific research or policy writing.

Yes, I am one of the law students who NEVER wanted to become a lawyer.

Had doubts the entire semester, did well on midterms (not too well, but well enough). Got asked to do environmental research abroad this summer (nothing related to law school).

Lately I have been CRAVING science. Can't focus as well as I would like on studying for finals. Not sure if it is because I find law school boring, dry, and full of people who are in it for the money, or because I actually want to pursue science. Is it giving up on myself? Or "following my dreams?"

I have until Wednesday to decide if I want to stay another semester or switch into my Masters program. (Masters could easily become PhD). I can re-enter law school Spring 2013 if I find it is what I want.

(Also-money is not a problem, received a generous scholarship/parents fronting the rest...have said I could pursue both and "not use" my law degree and they will be fine.)

Since I am assuming law school dropouts don't read r/lawschool, did any of you have doubts or know someone who decided to quit and purse another degree? THANKS. I know you all have finals...