Why is my box collider dissapearing when trying to edit its size?

I have tried to add a box collider to a sprite but the box collider spawned way out of the way of my scene. i had to move it all the way back to my scene and shrink it to meet the size of my sprite but when i zoom in so that I can correctly scale it to my sprite, the edit collider markers dissapear and it does not appear. It seems to be spawning way out of the way and massive and it hadnt done this before.