Congratulations on saving so much money to put toward your education.
With your $40K savings ($10k year), plus summer earnings, school year earnings, and the Federal Direct loan of $5,500 ($6,500 soph year and $7,500 each of the remaining two years) it sounds like you can afford around $20K/year. Now you will just have to wait to hear from ISU re: their full financial aid package which they will complete upon receiving your FAFSA…I hope they close the gap further from the $28K where they are right now.
Meanwhile are you applying elsewhere?