I can't determine a specific dollar amount used from my scholarship/student loans to pay for room and board and other expenses. How can I determine an estimate?

You may be able to estimate by looking at your tuition and room and board billing statements for the year and your scholarship and grant bills.   Your loan amounts are not relevant for the most part - you will only need to determine if any amount of scholarships were specifically allocated for this as that would make that scholarship money potentially taxable income to you. 

What you used the borrowed money for doesn't matter, since borrowed money is never taxable income to the borrower.

However, any scholarship or grant money used for anything other than qualified education expenses of tuition, books, and lab fees may be taxable income. (note that room and board is not a qualified education expense, but can be an "allowed" expense for 529 distributions.)

Jost log into your online college acount, go to the financials section of your account, and you can get a complete financial history down to the penny.