photoshop brush issue

[Toyeon220938799ng1]

In the middle of my working, my brush went kind of weird. The photo below is not a custom brush but a basic brush and basic air brush. It is not a brush-stair issu. I have reinstalled photoshop and updated all my drivers but it still just won't work. Can anybody help me. Sorry my english is bad.

[Toyeon220938799ng1]

Also my anti aliasing is on.