relax, as long as it was just a personal supply amount you can just write it off and forget about ever seeing it. i dont think the feds are going to go after you.
plus you can always just deny, deny, deny. they can't prove shit unless you used a credit card or something stupid like that to link yourself to it somehow.
I dont know how they do it now a days but years ago they sent it to you. Asked you to sign it and return it then if it happens again then you get the knock.