Dude, don't worry at all... You are 16, and by the sounds of it ("took me out of the dining room") this was some sort of resturant job or something... those are a dime a dozen, if you are responsible enough to hold this job for any amount of time, regardless if they fire you or not, you can hold another easily...

IF you think you are innocent, and they do take you back, look for another job regardless... and when you get one, which you will, walk right up to the dude, tell him your gone because of their attitude, and leave...

You don't need their reference, you don't need to put it on any future applications, you don't need to worry about being sued or getting into any more trouble... there are jobs out there for people willing to work hard and prove themselves, don't settle for some douche-bag resturant manager questioning your work moves..

and for future reference, keep the drugs out of the workplace.. if you have to buy pills from someone, at least take a smoke break or a bathroom break and leave the building before doing it right at work...