How can I tell her she needn't worry about me and would best leave me alone ?

See there is this thing called friendship where you actually care about someone else. She obviously considers you a friend and does not like to see you depressed (cuz ya are) And being like House is not something to be proud of he is an interesting character but in real life he would be miserable and on antidepressants. I'd say get some help. or just continuing on the way you are it's your choice but it's gonna be a lonely existence.