Was it a mistake to talk with my professor about my fear of substitute teaching?

I am in a Masters of Teaching Program and am going to start subbing to make some money. However, I am very apprehensive and nervous because of clroom management, I am still learning about this. I talked with my professor about how afraid I was and he was able to offer very few tips. Did this make me look incompetent, like I am not a viable teacher candidate? I want to be able to discuss my fears without coming across as "weak" or incapable, but plain and simple... subbing just sounds very frustrating in terms of clroom management and I admit to being afraid.