Describe lennie's state of mind as he goes to hide in the brush.

Lennie is extremely confused and scared. He knows he has done something terrible again but he can’t comprehend the details or the consequences for his actions. Lennie manifests his stress through visions:

Lennie's first vision is of his Aunt Clara, who raised him as a child. Although the vision is clearly the elderly woman-

'She wore thick bull's eye glasses and she wore a huge gingham apron with pockets..'

Her voice and words are Lennie's self-reproach.

His next vision also has Lennie's voice, but is not even human-

'Aunt Clara was gone, and from out of Lennie's head there came a gigantic rabbit'

Lennie clearly knows something bad is going to happen, he just does not know what. 

Lennie was thinking about fucking big fat black rabbits