Those were probley black flies. I usually use a stripper midge in a 22 or a black biot midge in a 20-22. During this hatch they get as picky as they come. Your just dealing with so many real bugs,it's hard to show them something at the exact moment they want to eat. Keep @ it. The more you run your fly through the more fish see it and are likely to eat. Just don't get in such a hurry you ruin your drift. I Know this sounds contradictory but it's a kinda hurry up and wait game.
What size tippet were you using? how long was your tippet. What indicator were you using? All these come into play. It,s a great game.