I know that "in over your head" means "involved in sth that is too difficult for you to deal with", but does "in away over your head" have the similar meaning? Can you help me out?
way over one's head = beyond one's understanding or competence, as in:
"The math required to complete these figures is way over my head."
way over one's head = out of one's depth or
in deep (over one's head) or beyond one's depth, as in:
"He was out of his depth in that advanced calculus class."
This expression alludes to being in water so deep that one might sink.
I would say
You are a way over your head when dealing with this situation.
You are in trouble here. You are in over your head.
I don't think I would use "a way" with the preposition "in"...it sounds awkward to me. They mean the same thing. "a way" does add a bit of emphasis though.