Color texture error

After 2 weeks of idleness on gmod (not playing), I launched it and played single player. The very first thing I noticed was the ground on Gm_construct.
It was normal color, but when i walked, medium sized squares of texture appear in different colors such as (they all are very light colors) blue, yellow,white, and red. oh and green.
Any suggestions to fix?

Post a screenshot?

Are you sure you didn’t smoke any drugs before playing?

More seriously:
I’ve never heard of this bug before,

some type of addon you have?

Notice: Only the center (more polished surface) is glitched, while the grass and cement are not.

I will go through some textures. I think I might of f***ed something up in my files.