Why do dairy products suddenly taste bad?

I have a weird problem that happened to me once when I was maybe 8 years old (I'm 20 now). I woke up one morning and all dairy products tasted horrible. They tasted as though they had gone bad. I'm not sure how long it lasted back then because I just stopped eating all dairy products for a couple of years — I was afraid they would taste bad, but it definitely lasted several months. When I started to have them again they tasted fine. It seems to have started again. What could possibly be the cause of this?


What to do about bleeding nose and gums?

I just came here this fall. Since then, my nose has been bleeding occasionally without any injury. My friend told me it was because of the dry air of U.S. Is he right? How can I prevent this situation? I also have a problem when I brush my teeth. My gums are always bleeding and not just a little!! What should I do? Thanks.