Help with teacher situation, please help :(?

Hey. I'm 18, female and about to finish school and exams in a weeks time (on friday) over the past 3 years ive developed extremely strong feelings towards my 3O year old female teacher. I'm a complete mess if im honest, shes alls I think about and id do anything to even get a glance of her. But, also, I think she feels the same as I catch her staring often, and sometimes when she looks at me she looks with a depressed look as if shes upset she likes me or something. One time she knocked my feet with hers under the table and she paused, lost concentration of what she was saying and stared for atleast 5 seconds before she continued speaking, I thought that was dodgy along with the staring. I just dont know what to do. Im so messed up and not looking forward to leaving school :( :( :( :( :( I feel I cant live without her!!