Why do i have dry mouth?!

Hi! I am a young healthy teen girl and for the last four days my mouth has been feeling dry.My mouth is not so dry that i can't eat or taste,bleeds,or burns but it is dry.I don't have diabetes i think, i pee normally,hungry like normal,my cuts heal quickly,and i am very energetic.Its been cold here in southern California but also there is been a cold bug getting my brothers sick around my house.I don't feel sick but in the last three days ago I've had a little bit of a stuffy nose and sneezing but that hasn't happened ever since then.I do drink plenty of water daily like normal and brush my tongue and teeth like before bedtime.My mouth does produce plenty of saliva but i feel that my tongue is rough and each time i breath thru my nose its dry.What could be causing my dry mouth?How long does it last?Have ever had dry mouth for long periods?