marijuana and my fifth amendment rights

I was recently arrested and charged with possesion of marijuana. My concern is that the judge will ask me where i got the drug from. Am i entitled to my fifth amendment rights in this situation, and can i decline to answer the question, knowing that my punishment might be worse if i dont answer?

You have 5th Amendment rights. ANd the judge doesn't ask you questions unless you plead guilty or testify in your own defense. But for g-d's sake ask the lawyer who is defending you!