SF86 and Omissions

[played1]

Like many people in the military I omitted a one time drug use in college when I enlisted. Fast foreword to this last summer, FED job comes up with poly associated with it. Omitted the drug use again, (I know, stupid) but i currently have a clearance and havent had any issues with it, current wont go over Secret/TS at most. During poly I pop on that question, dude has my card and like an idiot I said I had used.

I know the fed job is closed, along with any others, my fault i Understand but since im still in the reserves with this clearance what are the changes of blowback? I fully admit I was an idiot.