You just have to go on saying no.
So when she says “ lets do x today “, you say “ sorry but i have a lot of studying / housework to do / visit my granny “ .
And whatever she says you just go on saying No.
Oh my I really want to see that exhibition and i have no one else to go with.
Sorry that won’t work for me
Why not? You can see you gran later ?
I’m sorry have plans for that day / week.
But i hardly ever see you and i thought we were friends
Well I’m just really busy right now
But may cat has died and I’m upset.
I’m sorry to hear about your cat, but I’m busy / have plans .
What about next week / month?
I’m sorry I cant commit to anything .