morphine for cervical anterior disc replacement

My sister has been on about 120 mg of Morphine a day for a couple of months.  she hasn't always taken the full dose but right before her cervical anertior disc surgery last Tuesday that is how much she was taking a day.  She has 15 mg tablets and I know she was taking up to 4 twice a day right before the surgery.  She was taking the 60mg timed released ones for work (because she needed to be somewhat on the ball) but she said those didn't work, so at night she would take up to 4 of the 15mg tablets.  My question now is IS she addicted? The last couple days she pretty much tried to only take a few of the morphine tabs (2 at a time) with 2 percocets for breakthrough pain in between.  Yesterday she didn't take any morphine, only 2 perc every 4 hrs but last evening she threw up twice about 1 & 1/2 hrs after eating. Does anyone have any idea what her body might be doing? She started taking the morphine tabs again last night 3 @ 8 because she thought the perc was making her throw up.  She took 2 more in the night.  She is feeling better other than her pain of course. I was thinking of having her try the times released & none of the other stuff if she can.  See she only has 5 of the morphine tabs left and we are not in her hometown. So we won't be able to talk to her Dr. until tomorrow.  PLEASE ADVISE.....