Is there a word for someone who has the need to consult a professional for everything?

Someone who can't trust their own instincts or think for themselves.

...has low self-confidence.

An antonym of self-confidence is self-doubt.

"I agree," Steve uttered, "She is quite the self-doubter as she tends to seek someone else's point of view before even considering her own."

A related colloquial term is "Sheep".

a meek, unimaginative, or easily led person.

Broadly, it applies to anyone who unquestioningly believes in some particular source of information, especially if the speaker believes that source to be flawed. It isn't commonly used if you are trying to express something like "That person is consulting valid sources, but really shouldn't need help answering such a simple question".

When describing more specific situations I believe it is easier. For example, I am "hot handy", or "not skilled" when fixing things in the house. Whereas, someone could be simply and more generally "indecisive" if they always seek advice, before an important decision or choice.