Re: if only my friends knew...
I believe it's called Obesessive Complusive Disorder (OCD)...no seriously and here is why i think that!
she's Obsessed with her sis. (Hence, pinks reasoning applies here)
She's Complused to open threads on varying topic all pertaining to her sis
And it's Disorder because symptoms are there, and so is a cure! (quit being worried bout ur sis)