Hi, is it right to use didn't had anywhere?

For example if I say - what would you have chosen if you didn't had anything to worry about?

No, you can't say that!

As a lexical verb, "have" requires the help of "did" to form a negative or a question. "Did" is a kind of auxiliary verb, so the main verb (such as "have") that follows it is always in the plain (infinitive) form:

I have nothing to worry about. (positive)
Idid not/didn't have anything to worry about. (negative)
Did I have anything to worry about? (question)

PaulM