Today I got home from school and my cat was laying on a couch. So I went and layed next to her and put my head right by her. Before I layed down beside her she was licking herself, and when I layed next to her she started to lick the hair on my head. I pulled away startled but then I put my head back down and she started to do it again! She tried for 5-10 minutes. She even tried to lick my face. Why is she doing this?