DXM causes brain damage?

ok so I took some coricidin, I think it was 3 pills, 5 pills, then 7 pills, something like that. it was over the course of about 1 month. I also took some vick's cough syrup, about 1/2 bottle total during the same time period. now, after a month i feel a certain way, could it have caused brain damage of some kind? or did I not take enough?