If I pocket my last C/m and the Queen in a single strike, is this a win or a lose or do you put the pieces in the center again?
"If while shooting for the Queen you also sink one of your pieces, the Queen is automatically covered, no matter which went in first." Carrom.org
By this rule the game would be won along with the bonus for the Queen.
If queen goes first, then the cover goes, then it is secured; otherwise you have to cover it.