Asking me "are you ok?" highly irritates me!?

I guess i can call her my friend she is actually my sister's friend and i just grew up knowing her..Well my mom ped in 08 and every since then she's always asking "are you ok" and "whats wrong!?" The answer is I am fine! Im just an introvert! and i would think she would know that about me by now. The last time she came to my house and rang and banged at the door while singing "i know youre in there!" she did not let up until i came and answered the door... I live alone btw and she came unannounced I was asleep because i work overnights so when i came to the door looking wild and haggard after being abruptly awoken from sleep and not having time to put on something decent or to gather my thoughts what was the first thing out of her mouth? "ARE YOU OKAY!?" To her i am a charity case that needs 24--7 pity... how do i stop this?