Squint Right Eye. When Smiled Right Side Mouth Stays Down. What Could This Be?

Hi. So for the past few months, i have noticed that the right side of my face is having problems. I can feel everything fine, and see normally out of my eyes. The problem I have is my smile and my eye. When I smile, It feels normal, but if I see a picture my right side of my mouth stays down and the left side smiles normally. With my eye, it starts to turn in slightly and it is only noticable when I m tired, extremely stressed, or sometimes in pictures. The right eye also squints more, making my eye look a little smaller than the other. I am 15 years old, and I m not exactly sure what could be wrong. I do wear contacts and wore braces for almost 2 years, but I dont feel like that has anything to do with it. Basically my face sometimes gives off the apperance of being slanted and awkward. The reason I m asking now is because people have been noticing it a lot more and this happens to be a time where I am very tired and stressed. Once again I can feel my face normally and sometimes it feels a little bit number on the right side, but very slightly. What can this be?