knee pops ot of place when putting pressure slanted

by luciano herrera
(gilbert, AZ , us)

im 16 years old, about 4 years ago i was playing soccer and the ball was coming from the air i raised my right foot to the air and planted my left on the ground kinda slanted then i kicked and turn and thats when it started. i stopped playing for about 4 weeks then keep playing. 3 years later i played indoor soccer game and i plated my left foot on the ground slanted putting pressure on it untill my knee poped out, it dint hurt no pain but it was paranormal wierd. So oneday i did the same playing soccer and i put alot of pressure slanted my left knee inside and it popd out really hard it was painfull, now i dont know what to do.

now it just pops out of place when i put alot of pressure and now it kinda hurts from the ouside by my knee

PLEASE GIVE ME SOME ADVICE