All purely speculation but I'm thinking Abby had weight loss surgery.. When she got to LA she became stressed/anxious and over ate (we saw the shots of her stuffing her face). She then got really sick, which can possibly happen if you do that after having the surgery. If you don't chew food well enough, it can get lodged in/obstruct the lap band (not sure what kind of surgery she had, if any). If that happened, your doctor may have to intervene. Maybe she had to fly home to get her band adjusted or something. To me, she looked really ill when she came into the rehearsal looking very unkempt.