Can my boss legally do anything if he sees that I'm high as a kite, while I'm of work?

I was at my local bar. I had done about 3 grams before I even came to the bar. I was totally messed up. My bossed noticed me and said how are you doing. I couldn't even look him straight in the eye. I even had white powder on my nose and shirt. Can he send me for a drug test when I return to work. I feel that I should be able to do what I want after work. Please keep your comments to yourself, I bought legally had my head shop.