Programs From CS: a MSc, or another degree?

[Leonarte]

Hey guys,

So, I have been reading the forum for quite a time now. I am confused on what to do next in my academic life, and came here to ask your assistance.

I'm from Brazil, so we have to consider that the University system here is a bit different. By the end of this year I'll graduate from CS (just CS, we have no concept of minor or major here). The past year I've been working in a Combinatorial Optimization Research group, and it has been a wonderful experience. Now I've been offered, by my advisor, the possibility to continue working in the group on a MSc program starting next year.

The problem is that I'm not sure I want to go further in CS. I love programming, I really do, but I like to do it applied to math or physics (thus why I got interested in Combinatorial Optimization). Also I love math and physics and studying the nature of things. I have been checking the Physics and the Applied Math undergraduate programs at my university and I really felt like moving to one of them, specially physics (I've came to know that the department here is in lack of good programmers, so...).

Questions:

1. Should I change to Physics or Ap. Math (let's not consider which one yet)?
   
2. Would I be throwing away a big opportunity (I basically have a MSc on my hands)?

Notes: As notes, I'll let some information that may be helpful for anyone trying to help me.

1. In CS I have studied Calculus I and II, Discrete Maths, Linear Algebra I, Probability and Statistics, Graph Theory, Combinatorial Analysis, Combinatorial Optimization and Physics I (those are the most relevant to Physics and/or Ap. Math I guess). In the next, and last semester, I'm going to try Mathematical Analysis A, and ODE or Linear Algebra II.
2. As for what I want to work with, I want to be a professor at an University teaching and doing research. If that does not work out, at least work at a company also doing research.
   
3. I can't try going into a Physics MSc program here because one must have a degree on physics to do so. I could try one in Math, but I'm pretty sure I wouldn't have the necessary knowledge.
4. Just as a reminder, in Brazil our university programs do not have a major/minor concept, you do either CS or Physics, not "both" (although you can take some classes of other programs, that does not give you any additional title).
5. As a last thing, I'm 22 years old (some people say it matter, some don't).

 

[Leonarte]

If there is anything I can make clearer, or any additional information I can give, please feel free to ask.
I could use some help :)