@azygous is right that chickens notice. It's amazing how much it matters that other birds don't feel like you're picking favorites.You may still visit and cuddle her, but try to treat her as you treat the others, even showing her that the others are as loved as she is. Yes, chickens notice these things.
I completely relate to your [adorable, adorable] problem. I'm 100% at our birds' service and will let my limbs go numb before evicting a chicken from my lap. But part of my dedication to them includes creating an environment where birds function successfully as a group. It's good advice to wean her because this is a critical time for forming relationships with her chicken peers. Being singled out or absent from the flock could lead to bullying that worsens with age.
Is she bullied at all in the brooder now, or does she have any obvious health issues like pasty butt that would be causing her to squall so much? If not, it's likely best to let her cry it out for longer and longer periods (the path it sounds like you're taking). And maybe when you have her out with you, have all the chicks out together. Hopefully she'll transfer that attachment to another biddie in the brooder. Best of luck!