Modify formula using indirect to work with autofill?

Here are the first few rows:

=INDEX(INDIRECT("'"&I$2&"'!G:G"),MATCH(INDIRECT("'"&I$2&"'!C12"),INDIRECT("'"&I$2&"'!C:C"),"0"))
=INDEX(INDIRECT("'"&I$2&"'!G:G"),MATCH(INDIRECT("'"&I$2&"'!C13"),INDIRECT("'"&I$2&"'!C:C"),"0"))
=INDEX(INDIRECT("'"&I$2&"'!G:G"),MATCH(INDIRECT("'"&I$2&"'!C14"),INDIRECT("'"&I$2&"'!C:C"),"0"))
=INDEX(INDIRECT("'"&I$2&"'!G:G"),MATCH(INDIRECT("'"&I$2&"'!C15"),INDIRECT("'"&I$2&"'!C:C"),"0"))

If I try to autofill down (~50 rows) it just repeats C12, C13, C14, C15, C12, C13, etc, etc.

I need the INDIRECT to reference a sheet name by a cell value.

I don't really want to change all 50+ of these. How can I rewrite this formula to respect autofill?