Just make sure she is always seperated from other birds and every time you touch her wash your hands well because the sickness from the bird can easily get to the others.

She sounds very sick and needs to be in a quiet room with the cage half covered and make sure no drafts are around.

Maybe she has an infection behind her eye.

Whatever the case she's sick and needs to be alone only touch her when needed...as said watch her appetite and make sure she's drinking lots of water since birds can get dehydrated very fast especially when sick.

Also watch those poops make sure there regulare and not drippy.

Good luck hope she purks up and gets restored to full health.