This seems really strange. With your stats you should have gotten some sort of merit scholarship (genuinely not trying to make you feel bad or brag) but I received a merit scholarship with an ACT 5 points less than yours, so the fact that you have a 34 ACT and no merit scholarship is odd. Perhaps it was a mistake? Did you mention your concussion on the common app, or somewhere else where they could read about it? What is your EFC? They shouldn’t take that into account for giving a merit scholarship but maybe they did. Have you tried contacting them and asking them? Did you turn your application in before the November 1st deadline? I’m pretty sure they don’t award merit scholarships unless you hit that deadline. I hope this all works out for you.
I think OSU is sporadic at best with need-based aid. I believe I got a generous amount but it still baffles me when other people do not.