Restaurant Laws in DC?

I work in a restaurant in DC, and need a few questions answered concerning taxes and minimum wage.

The first concerns my hourly wages and taxes. When I began working there, I was never given a form to fill out for tax claims, and every two weeks (regardless of the number of hours I work or how much I make in tips) I receive a voided check; apparently everything goes straight to taxes. I also don't claim my own taxes.

My second question is about the minimum wage... Once a week I work as a busboy and am paid $25 for a 6-7 hour shift. In this restaurant, busboys also act as baristas and food runners, and they receive 20% of the servers' tips. If this means that the busboy only qualifies for the minimum wage for servers, the $25 isn't so bad, but if the busboy should receive regular minimum wage, I'm getting screwed...

Is anyone very familiar with this topic or know where I should turn for advice?