Ihave A Sharp Shooting Pain In My Upper Left Buttock

Ihave a sharp shooting pain in my upper left buttock that runs down behind my knee. it is most intense when I sit for more than 15 minutes and excruciating when I get out of bed . 600 mg ibuprofen relieve but do not alleviate pain. I have an orthopedic apt but am going on vacation before and wonder if there is anything I can do Besides increase dosage) for the pain it is getting worse every day. Friends all say sciatica?