Is there a vaporizer in the house? Ask your aunt. I prefer a warm air -- but a cool air will do. Either will loosen the congestion and help you to breathe. Close your door so the "steam/vapor" will stay in YOUR room.

If they don't have a vaporizer -- ask them to GET one -- until then, go into the bathroom, shut the door, turn on the shower -- hot water full blast, and sit on the toilet and breathe the steam for 10 to 15 minutes. Then, blow your nose to get as much junk out as possible. Once you are clearer, go take a nap.