Really Wierd Glitch with movement.

Frazzle

I'm creating a gravity platformer, where if you press space you change the gravity angle to gravity angle +180. But sometimes when I change gravity,don't move while the player's y motion isn't 0, when i move left or right the player collides with the ground,even thought it's beneath them.

Any ideas?

If you need a more in-depth description i'll make then post a video.