Is it appropriate to ask a professor about continuing my degree? I'm in a very unfortunate situation. I have B.S. from Computer Science and I change my field to Applied Mathematics for M.S. (because of recommendations of my colleagues from research).
In CS I was pretty good, I finished with Dean's award for Bachelor thesis (that's why I was offered a part-time position in research), but now I'm struggling heavily to even pass the first term in Math. CS program was concentrating on programming, so we had only single-variable calculus, basics of linear algebra and some graph theory.
Now I must take exams from Functional Analysis, Complex variables, Partial differential equations etc. and I'm afraid I'll not be able to pass them. I was able to pass lesser tests and projects, but I need a lot of time for every single problem and now, before exams, I see how many things I don't understand.
Additionally I'm suffering from high-blood pressure since I was 15, but now is my condition worsening very fast (probably because of stress). I feel tired, depressed and dizzy very often.
So, is it appropriate to ask the one professor, who is the head of department, about possibilities of suspension or simply going again into the first year of M.S. next year?
Maybe I'd like to ask him about his opinion about my talent for this, because I've never experienced such setback in school and so it's possible I'm simply too silly to comprehend Math.
EDIT:
I'm studying in the Czech Republic.
To me it never hurts to discuss possible options. Complex mathematics can be a difficult hurdle to cross and it seems you're making a leap from basic math to university-level math without being prepared for it. 

Explain your situation in detail. I'm sure this isn't a first for the head of your department and maybe (s)he can suggest some courses which might help you in catching up with the program.

I'd keep your high blood pressure problem out of the discussion.