While covering the Queen, if a player pockets the last C/m of his own together with the striker
The game will continue, returning the pocketed C/m along with a penalty. If the stroke was proper, your turn continues with you trying to cover the Queen. From the ICF rules:


  
  a) While covering the Queen by a proper stroke, if a player pockets the striker along with his C/m, the C/m so pocketed plus one
  C/m as Due shall be taken out for placing by the opponent. The player shall however, continue his turn. If in that subsequent stroke no C/m of the player is pocketed, the Queen shall not be considered to have been covered and it shall be taken out for placing.
  
  b) While covering the Queen, if a player pockets his Striker along with his C/m by an improper stroke, the C/m so pocketed plus two C/m as due and penalty shall be taken out for placing by the opponent and the player shall lose his turn. The Queen shall be taken out for placing by the Umpire.