How To Treat Sticky Hairs?

I'm 15 years old. I shower every night before I go to sleep but a lot of the times when I wake up my hair feels sticky. The first few times I figured I rushed the shower and didn't rinse it enough, but this proved not to be true when I throughouly rinsed for 5 minutes. I don't understand! I've been using head and shoulder for 3 years and it has never failed me! the great spot is on the top of my head near my hair part, it's extremely noticeable and I need help!