What they told me recently is that if you are taking short acting pain medications 5 or more times a day, then you might benefit more from a longer acting opiate.
And though they write "every 4 hours", the assumtion is that you will not be taking the medication nearly that much. 135 pills for 15 days would be around 3 a day. Again, the assumption is that there will be days when you may need 5, and then other days you may be able to get by with much less. On days when I'm not doing much, I tend to just hang out on the couch and not take my meds, to conserve them.
But I agree with Flower. If you are taking it 5 times a day, every day, without fail, then you may need a different choice, and will need to either call (worth a try) or have a face to face visit before the holidays.
Question...Did you tell your pain doctor that you do take five per day and not three? Can you set up another appointment to see her before the holiday? Sometimes it's better to address medication changes face to face, and sometimes pain contracts say that you have to do so face to face. So, if she does know that you take five a day and she just wrote the script wrong then I would call. But, if she thinks that you are taking three a day then I would get set up with an appointment. Hopefully others will chime in with advice.