and derek runs to mrs webb...?

He ran to the school

Miss Blake is a teacher there and so he found her

Allison isn't crazy

this was a good ep for her

but she hallucinated...

She's kind of traumatized

also, there are lots of hints about why that is happening and lots of fan theories

and none of them involve her being crazy

Also you might want to go look at Jeff's ask sessions, he does them every Sunday teenwolf