Quinton Aaron says what he believed to be a mere cold turned out to be something way more serious ... which he never would've caught had he not gotten checked out.
"The Blind Side" star -- who played the co-lead, Michael Oher, in the flick -- scared the crap out of people Tuesday when he posted a video of himself bedside in a hospital, saying he was gonna be alright ... but not disclosing what the heck was wrong with him.
I Appreciate the love and prayers and continue to have faith that it's all gonna be ok!