To say, "my doctor" would it be "benim doktorum" and, if so, is the "benim" required to distinguish it from "I am a doctor" or can you rely on context and simply say, "doktorum"?
Context normally will let you know :) If you say it randomly out of context, it is impossible to tell. :)
Will only "doktorum" work? Thanks in advance!
In this case, yes :) You have to have the personal ending -um to get the meaning of "I am..."
Yes, but "doktorum" also means "my doctor" so i suggest using "ben" in the sentence.